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P3 04 The Eye 210 minutes 210 marks Q1. The diagrams show how the same two lenses can be used to make a microscope or a telescope. The microscope and the telescope made from the two lenses are similar in some ways but different in others.
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P3 04 The Eye
210 minutes
210 marks
Q1. The diagrams show how the same two lenses can be used to make a microscope or a telescope.
The microscope and the telescope made from the two lenses are similar in some ways but different in others.
Complete the table to show these similarities and differences.
(Total 7 marks)
Q2. Lenses are used in many optical devices.
Complete the table below about the images formed by some optical devices.
OPTICALDEVICE
NATURE OFIMAGE
SIZE OFIMAGE
POSITION OFIMAGE
Eye real
Projector Magnified
camera Closer to lensthan the object
(Total 6 marks)
Q3. The diagram shows the image IC formed by a lens, of an object OB a long way from it. The points F mark the focal points of the lens.
(a) Describe, either by writing below or drawing on the diagram, how the size and position of the image changes:
(i) when the object OB is moved towards the focal point F.
.........................................................................................................................
.........................................................................................................................
(ii) when the object OB is moved past F to a point nearer the lens than the focal point.
.........................................................................................................................
.........................................................................................................................(4)
(b) Explain how a converging lens in a camera is used to produce sharp images on the film when the object is a long distance away from the camera, and when it is close to the camera.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................(3)
(Total 7 marks)
Q4. (a) The diagram shows two parallel rays of light, a lens and its axis.
(i) Complete the diagram to show what happens to the rays.
(2)
(ii) Name the point where the rays come together.
...........................................................................................................................(1)
(iii) What word can be used to describe this type of lens?
...........................................................................................................................(1)
(b) The diagram shows two parallel rays of light, a lens and its axis.
(i) Which point A, B, C, D or E shows the focal point for this diagram?
Point ..................(1)
(ii) Explain your answer to part (b)(i).
...........................................................................................................................
...........................................................................................................................(1)
(iii) What word can be used to describe this type of lens?
...........................................................................................................................(1)
(c) Complete the following three sentences by crossing out the two lines in each box which are wrong
film
In a camera a converging lens is used to produce an image on a lens .
screen
The image is
larger than
smaller than
the same size as
the object.
Compared to the distance of the image from the lens, the object is
further away from
nearer to
the same distance from
the lens.(3)
(d) Explain the difference between a real image and a virtual image.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................(3)
(Total 13 marks)
Q5. (a) The diagram shows a lens used as a magnifying glass. The position of the eye is shown and the size and position of an object standing at point O.
(i) What type of lens is shown in the diagram?
...........................................................................................................................(1)
(ii) Two points are marked as F. What are these points?
...........................................................................................................................(1)
(iii) What is the name of the straight line which goes through the point F, through the point L at the centre of the lens, and through the point F on the other side?
...........................................................................................................................(1)
(iv) On the diagram, use a ruler to construct accurately the position of the image. You should show how you construct your ray diagram and how light appears to come from this image to enter the eye.
(5)
(v) The image is virtual. What is a virtual image?
...........................................................................................................................
...........................................................................................................................(1)
(b) The lens shown in the diagram in part (a)(iv) can be used in a camera to produce a realimage.
Explain why a real image must be produced in a camera and how the object and the lens are positioned to produce a real image which is smaller than the object.
Do not draw a ray diagram as part of your answer.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................(3)
(Total 12 marks)
Q6. Malik uses a camera to photograph the Moon.
(a) Complete each sentence by choosing the correct words from the box.
You may use each word once, more than once or not at all.
converging diverging image longer
object real shorter virtual
In a camera a ........................................ lens is used to produce an ............................
of an ........................................ on a film. The ........................................ is smaller than
the ........................................ and it is a ........................................ distance from the lens.(6)
(b) The Moon moves in a nearly circular path around the Earth.
(i) What is the name of the force which causes the Moon to move around the Earth?
...........................................................................................................................(1)
(ii) In which direction does this force act?
...........................................................................................................................(1)
(c) A force is needed to make a car change direction when it goes round a bend.
(i) What is the name of this force and where does it act?
...........................................................................................................................
...........................................................................................................................(2)
(ii) Complete the two spaces in the sentence.
The force needed is greater if the ........................................ of the car is greater and
the ........................................ of the bend is smaller.(2)
(d) What word is used to describe any force which causes an object to move in a circular path?
....................................................................................................................................(1)
(Total 13 marks)
Q7. (a) The diagram shows how parallel rays of light pass through a convex lens.
(i) Mark the position of the focus.
(1)
(ii) Is this a converging lens, a diverging lens, both or neither?
.........................................................................................................................(1)
(b) The diagram shows how parallel rays of light pass through a concave lens.
(i) Mark the position of the focus.
(1)
(ii) Is this a converging lens, a diverging lens, both or neither?
.........................................................................................................................(1)
(c) Complete these sentences by crossing out the two lines in each box that are wrong.
In a camera, a lens is used to produce an image of an object on a .
The image is the object.
The image is the lens, compared to the distance of the object from the lens.
(4)
(d) In a cinema projector, a convex lens is used to produce a magnified, real image.
(i) What does magnified mean?
.........................................................................................................................
.........................................................................................................................(1)
(ii) What is a real image?
.........................................................................................................................
.........................................................................................................................(1)
(e) You are in a dark room. You have a box containing some lenses. Only one of them is aconverging lens.
Describe how, by just feeling the lenses, you can pick out the converging lens.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................(2)
(Total 12 marks)
Q8. (a) A student investigated the refraction of light as it passes out of a transparent plastic block.
She aimed a ray of light at point X. She marked the position of the ray as it passed through the transparent plastic block and into the air.
The angle i is the angle of incidence.
(i) What is the name of angle r?
..........................................................................................................................(1)
(ii) What is the name of the dashed line?
..........................................................................................................................(1)
(b) A camera uses a lens to produce an image which falls on a light detector.
Name a light detecting device which may be used in a camera.
....................................................................................................................................(1)
(c) The diagram shows the position of an image formed in a camera.
(i) What type of lens is shown in the diagram?
..........................................................................................................................(1)
(ii) Use the equation in the box to calculate the magnification.
magnification =
Show clearly how you work out your answer.
..........................................................................................................................
..........................................................................................................................
Magnification = ....................(2)
(d) Why does the image formed in a camera have to be a real image?
....................................................................................................................................
....................................................................................................................................(1)
(Total 7 marks)
Q9. The diagram shows an object located vertically on the principal axis of a diverging lens. A student looks through the lens and can see an image of the object.
(a) Using a pencil and ruler to draw construction lines on the diagram, show how light from the object enters the student’s eye and the size and position of the image.
(3)
(b) Describe the nature of the image by comparing it to the object.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................(2)
(Total 5 marks)
Q10. The ray diagram shows the position and size of the image, I, of an object, O, formed by a lens, L.
(a) What type of lens is shown in the ray diagram?
.....................................................................................................................................(1)
(b) Name the point labelled P.
.....................................................................................................................................(1)
(c) The ray diagram has been drawn to scale.
Use the equation in the box to calculate the magnification.
Show clearly how you work out your answer.
.....................................................................................................................................
.....................................................................................................................................
Magnification = ..............................(2)
(d) How can you tell from this ray diagram that the image is a real image?
.....................................................................................................................................
.....................................................................................................................................(1)
(Total 5 marks)
Q11.The diagram shows two lenses, A and B. Two rays of light are shown incident on the left-hand surface of each lens.
Lens A Lens B
(a) On the diagram, draw lines to show how the light passes through each lens into the region within the dotted lines.
(3)
(b) A student has short sight because his eyeball is too long. This produces a blurred image.
To be able to see clearly, the student wears glasses.
Which lens, A or B, should be used in the student’s glasses?
Write your answer in the box.
Explain how your chosen lens corrects the student’s short sight.
........................................................................................................................
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........................................................................................................................(5)
(c) It is sometimes possible to correct short sight by having the cornea of the eye reshaped.
What device is used by a surgeon to reshape the cornea?
Draw a ring around one answer.
drill laser scalpel(1)
(Total 9 marks)
Q12. The diagram shows a ray of light passing through a diverging lens.
(a) Use the information in the diagram to calculate the refractive index of the plastic used to make the lens.
Write down the equation you use, and then show clearly how you work out your answer.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
Refractive index = ..................................(2)
(b) The focal length of the lens is 5 cm. A student looking through the lens sees the image of a pin.
Complete the ray diagram below to show how the image of the pin is formed.
(3)(Total 5 marks)
Q13. The ray diagram shows a converging lens being used as a magnifying glass.The diagram has been drawn to scale.
(a) What name is given to the type of lens used as a magnifying glass?
........................................................................................................................(1)
(b) Calculate the magnification produced by the lens.
Write down the equation you use, and then show clearly how you work out your answer.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
Magnification = .....................................(2)
(c) Describe the image produced by a magnifying glass.
........................................................................................................................
........................................................................................................................
........................................................................................................................(3)
(Total 6 marks)
Q14. A student investigated how the nature of the image depends on the position of the object in front of a large converging lens.
The diagram shows one position for the object.
(a) Use a ruler to complete a ray diagram to show how the image of the object is formed.
(4)
(b) Describe the nature of this image relative to the object.
........................................................................................................................
........................................................................................................................
........................................................................................................................(2)
(Total 6 marks)
Q15. A student investigates how the magnification of an object changes at different distances from a converging lens.
The diagram shows an object at distance d from a converging lens.
(a) (i) The height of the object and the height of its image are drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens shown in the diagram.
Show clearly how you work out your answer.
...............................................................................................................
...............................................................................................................
...............................................................................................................
Magnification = ............................................................(2)
(ii) The points F are at equal distances on either side of the centre of the lens.
State the name of these points.
...............................................................................................................(1)
(iii) Explain how you can tell, from the diagram, that the image is virtual.
...............................................................................................................
...............................................................................................................(1)
(b) The student now uses a different converging lens. He places the object between the lens and point F on the left.
The table shows the set of results that he gets for the distance d and for the magnification produced.
Distance dmeasured in cm
Magnification
5 1.2
10 1.5
15 2.0
20 3.0
25 6.0
His friend looks at the table and observes that when the distance doubles from 10 cm to 20 cm, the magnification doubles from 1.5 to 3.0.
His friend’s conclusion is that:
The magnification is directly proportional to the distance of the object from the lens.
His friend’s observation is correct but his friend’s conclusion is not correct.
(i) Explain, with an example, why his friend’s conclusion is not correct.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................(2)
(ii) Write a correct conclusion.
...............................................................................................................
...............................................................................................................(1)
(iii) The maximum range of measurements for d is from the centre of the lens to F on the left.
The student cannot make a correct conclusion outside this range.
Explain why.
...............................................................................................................
...............................................................................................................(1)
(Total 8 marks)
Q16. At night, it is important that the lights of a car can be seen by other drivers but it is dangerous if these lights dazzle them.
The diagram shows a rear light of a car.
(a) (i) Name part A.
...............................................................................................................(1)
(ii) Name the process which occurs at point B and at point C.
...............................................................................................................(1)
(b) A headlamp of a car contains a lens.
The ray diagram shows the position and size of the image, I, of an object, O, formed by a lens similar to the one inside a car headlamp.
(i) What type of lens is shown in the ray diagram?
Draw a ring around your answer.
converging diverging plane(1)
(ii) The ray diagram is drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens.
Show clearly how you work out your answer.
...............................................................................................................
...............................................................................................................
Magnification = ..............................(2)
(Total 5 marks)
Q17. The diagram shows a lens, the position of an object and the position of the image of the object.
(a) What type of lens is shown?
........................................................................................................................(1)
(b) What is the name of the points, F, shown each side of the lens?
........................................................................................................................(1)
(c) (i) The image is real and can be put on a screen.
How can you tell from the diagram that the image is real?
...............................................................................................................
...............................................................................................................(1)
(ii) Draw a ring around a word in the box which describes the image produced by the lens.
inverted larger upright
(1)
(d) A student investigates the relationship between the distance from the object to the lens and the magnification produced by the lens.The student’s results are given in the table.The student did not repeat any measurements.
Distancein millimetres
Height of objectin
millimetres
Height of imagein
millimetres
Magnificationproduced
40 20 58 2.9
50 20 30 1.5
60 20 20 1.0
70 20 14 0.7
80 20 12 0.6
90 20 10 0.5
The student plots the points for a graph of magnification produced against distance.
(i) Draw a line of best fit for these points.(1)
(ii) Complete the following sentence by drawing a ring around the correct word in the box.
A line graph has been drawn because both variables are
categoric.
described as being continuous.
discrete.
(1)
(iii) Describe the relationship between magnification produced and distance.
...............................................................................................................
...............................................................................................................
...............................................................................................................(2)
(Total 8 marks)
Q18. The ray diagram shows the image formed by a concave mirror.
Use the equation in the box to calculate the magnification.
Show clearly how you work out your answer.
........................................................................................................................
........................................................................................................................
Magnification = ...............................................(Total 2 marks)
Q19. (a) The diagram shows a converging lens being used as a magnifying glass.
(i) On the diagram, use a ruler to draw two rays from the top of the object which show how and where the image is formed. Represent the image by an arrow drawn at the correct position.
(3)
(ii) Use the equation in the box to calculate the magnification produced by the lens.
Show clearly how you work out your answer.
...............................................................................................................
...............................................................................................................
Magnification = ........................................(2)
(b) A camera also uses a converging lens to form an image.
Describe how the image formed by the lens in a camera is different from the image formed by a lens used as a magnifying glass.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................(2)
(Total 7 marks)
Q20. The diagram shows a lens being used as a magnifying glass.
(a) (i) What type of lens is shown in the diagram?
Draw a circle around your answer.
concave converging diverging(1)
(ii) Use the equation in the box to calculate the magnification produced by the lens.
The object and image in the diagram have been drawn to full size.
Show clearly how you work out your answer.
...............................................................................................................
...............................................................................................................
Magnification = ........................................(2)
(b) The diagram shows how the image changes when the object has been moved closer to the lens.
Complete the following sentence by drawing a ring around the correct line in the box.
increases
Moving the object closer to the lens does not change
the magnification produced
decreases
by the lens.(1)
(Total 4 marks)
Q21.A student investigates how the magnification of an object changes at different distances from a converging lens.The diagram shows an object at distance d from a converging lens.
(a) (i) The height of the object and the height of its image are drawn to scale.
Use the equation in the box to calculate the magnification produced by the lens shown in the diagram.
magnification =
Show clearly how you work out your answer.
...............................................................................................................
...............................................................................................................
...............................................................................................................
Magnification = ..................................................(2)
(ii) The points F are at equal distances on either side of the centre of the lens.
State the name of these points.
...............................................................................................................(1)
(iii) Explain how you can tell, from the diagram, that the image is virtual.
...............................................................................................................
...............................................................................................................(1)
(b) The student now uses a different converging lens. He places the object between the lens and the point F on the left.
The table shows the set of results that he gets for the distance d and for the magnification produced.
Distance dmeasured in cm Magnification
5 1.2
10 1.5
15 2.0
20 3.0
25 6.0
His friend looks at the table and observes that when the distance doubles from 10 cm to 20 cm, the magnification doubles from 1.5 to 3.0.
His friend’s conclusion is that:
The magnification is directly proportional to the distance of the object from the lens.
His friend’s observation is correct.
His friend’s conclusion is wrong.
(i) Explain using data from the table why his friend’s conclusion is wrong.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................(2)
(ii) Write a correct conclusion.
...............................................................................................................
...............................................................................................................(1)
(iii) The maximum range of measurements for d is from the centre of the lens to F on the left.
The student cannot make a correct conclusion outside this range.
Explain why.
...............................................................................................................
...............................................................................................................(1)
(Total 8 marks)
Q22.An event involved paddling a homemade raft down a fast-flowing river. The rafts were made using empty barrels.
By Reidrac [CC BY-SA 2.0], via Flickr
Below are the designs of two rafts.
(a) Compare the stability of the two raft designs. Give reasons for your answer.
........................................................................................................................
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........................................................................................................................
........................................................................................................................
........................................................................................................................(2)
(b) A camera was used to take photographs of the rafts. The camera contains a convex (converging) lens.
Complete the ray diagram to show how the lens produces an image of the object.
F = Principal focus(4)
(c) State two words to describe the nature of the image produced by the lens in the camera.
1 ........................................................................................................................
2 ........................................................................................................................(2)
(Total 8 marks)
Q23.An event involved paddling a homemade raft down a fast-flowing river. The rafts were made using empty barrels.
By Reidrac [CC BY-SA 2.0], via Flickr
(a) (i) Which two factors would most affect the raft’s stability?
Tick ( ) the two correct factors.
The cost of the raft
The width of the base of the raft
The position of the centre of mass of the raft
How streamlined the raft is
(2)
(ii) Here are three raft designs:
Which design of raft would be most stable?
Tick ( ) one box.
Design A
Design B
Design C
(1)
(b) A camera was used to take photographs of the rafts. The camera contains a convex (converging) lens. The ray diagram shows how the lens produces an image.
F = Principal focus
(i) Which two words from the list describe the nature of the image?
Draw a ring around each of the two correct answers.
upright magnified inverted virtual real
(2)
(ii) Use information from the ray diagram to calculate the magnification of the image.
Use the correct equation from the Physics Equations Sheet.
...............................................................................................................
...............................................................................................................
...............................................................................................................
Magnification = ..............................(2)
(c) A different type of lens is a concave (diverging) lens.
Which diagram shows a concave (diverging) lens?
Tick ( ) one box.
(1)
(Total 8 marks)
Q24.When glass is placed in a liquid of the same refractive index, the glass seems to disappear. This method can be used to determine the refractive index of small pieces of glass.
(a) The refractive index of some types of glass and some liquids is given in the table.
Type of glass Refractiveindex Liquid Refractive
index
Bakeware glass 1.47 Methanol 1.33
Car headlight 1.48 Water 1.33
glass
Window glass 1.50 Alcohol 1.37
Bottle glass 1.52 Olive oil 1.47
Spectacle glass 1.54 Castor oil 1.48
Lead glass 1.62 Cinnamon oil 1.60
(i) Use information from the table to give an example of a type of glass and a liquid where the glass would seem to disappear.
Type of glass .................................................................
Liquid .................................................................(1)
(ii) What is the range of refractive index of the liquids in the table?
From ........................................ to ........................................ .(1)
(iii) Which type of glass has a refractive index outside the range for the liquids?
................................................................................................................(1)
(b) The diagram shows a ray of light travelling from air into glass.
(i) What is the name given to the dashed line?
................................................................................................................(1)
(ii) Draw, on the diagram, the letter i to label the angle of incidence.(1)
(iii) Draw, on the diagram, the letter r to label the angle of refraction.(1)
(i) The value of i is 46° and the value of r is 29°.
Calculate the refractive index of the glass.
Use the correct equation from Section B of the Physics Equations Sheet.
................................................................................................................
................................................................................................................
Refractive index = ........................................(3)
(ii) Look at the table in part (a).
Name a type of glass that could have been used in part (b).
................................................................................................................(1)
(Total 10 marks)
Q25.(a) The diagram shows a section through a human eye.
(i) Use words from the box to label the diagram.
Ciliary muscle Cornea Iris Lens Pupil Retina
(4)
(ii) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
Describe the functions of the ciliary muscle and the iris.
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(b) Draw a ring around the correct answer to complete the sentence.
Long sight can be caused by the
eyeball being too long.
eyeball being too short.
cornea being irregularly shaped.
(1)
(c) The diagram shows how a convex lens forms an image of an object.
This diagram is not drawn to scale.
(i) Which two words describe the image?
Draw a ring around each correct answer.
diminished inverted magnified real upright
(2)
(ii) The object is 4 cm from the lens. The lens has a focal length of 12 cm.
Calculate the image distance.
Use the correct equation from Section B of the Physics Equations Sheet.
................................................................................................................
................................................................................................................
................................................................................................................
Image distance = ................................ cm(3)
(d) What does a minus sign for an image distance tell us about the nature of the image?
.........................................................................................................................(1)
(Total 17 marks)
Q26.Light changes direction as it passes from one medium to another.
(a) Use the correct answer from the box to complete the sentence.
diffraction reflection refraction
The change of direction when light passes from one medium to another
iscalled ......................................................... .(1)
(b) Draw a ring around the correct answer to complete the sentence.
When light passes from air into a glass block, it changes
direction
away from the normal.
towards the normal.
to always travel along the normal.
(1)
(c) Diagram 1 shows light rays entering and passing through a lens.
Diagram 1
(i) Which type of lens is shown in Diagram 1?
Draw a ring around the correct answer.
concave convex diverging
(1)
(ii) In Diagram 1, what is the point X called?
................................................................................................................(1)
(d) A lens acts like a number of prisms.
Diagram 2 shows two parallel rays of light entering and passing through prism A and prism C.
Diagram 2
Draw a third parallel ray entering and passing through prism B.(4)
(e) What two factors determine the focal length of a lens?
1 .....................................................................................................................
2 .....................................................................................................................(2)
(f) A converging lens has a focal length of 20 cm.
Calculate the power, in dioptre, of the lens.
Use the correct equation from Section B of the Physics Equations Sheet.
.........................................................................................................................
.........................................................................................................................
Power of the lens = .................................... dioptre(2)
(Total 12 marks)
M1. makes things look bigger/clearer/nearer M used for small objects;or to see things better T used for distant objects
magnifies or makes it bigger
‘it’ = image of object; bigger for M;inverted/upsidedown/ other way up smaller for Tany seven for 1 mark each
[7]
M2. Eye – Diminished/smaller than objectNearer the lens than object or on the retina
for 1 mark each2
Projector – realFurther from lens than object
for 1 mark each2
Camera – realSmaller (than object)
for 1 mark each2
[6]
M3. (a) (i) Image distance increasesImage size increasesRemains invertedRemains real
for 1 mark each2
(ii) Image distance decreasesImage size decreasesBecomes uprightBecomes virtual
for 1 mark each2
(b) Move lens with respect to filmCloser for distant objectsFurther for near objectsfor 1 mark each
3[7]
##
(a) (i) rays continued to meet on the right hand side of the lens and beyond
must be straight lines from the right hand side of the lensignore details through the lensallow if no arrows
1
meet exactly on the axisnegate mark if contradictory arrow(s) addeddo not need to go beyond the focus for this mark
1
(ii) (principal) focusor focal (point)
1
(iii) convergingor convex
1
(b) (i) A1
(ii) rays seem to come from this pointor words to this effector shows this on the diagram
1
(iii) divergingor concave
1
(c) filmaccept any unambiguous method of showing the correct response
1
smaller than1
further away from1
(d) any three from:
• real image can be put on a screenallow film
• virtual image cannot be put on a screen / film
• virtual image is imaginary
• real image is formed where (real) rays cross / convergeallow real image has light travelling through it
• virtual image is where virtual / imaginary rays (seem to) come fromor virtual image is where rays seem to come from
• virtual image formed where virtual rays intersect / cross3
[13]
M5. (a) (i) converging / convex / biconvex1
(ii) focal (points) or fociaccept focuses or focus (point)
1
(iii) (principal) axis1
(iv)
all lines drawn with a ruler for full marks
no ruler, penalise 1 mark from first four
last mark can still be awarded
double refraction drawn could get 4 out of 5 marksray that continues from the top of the object through Lto the eye
1
horizontal ray from the top of the object, refracted by the lensand continued through F on the r.h.s. to the eye
1
back projections of these rays (shown as dotted lines)1
image 25 mm high at 61 mm left of L(tolerance 1 mm ± vertically, 2 mm ± horizontally)
1
at least one arrow shown on real ray and towards the eyebut do not credit if contradicted by other arrow(s)
1
(v) formed where imaginary rays intersect / cross or not formed by real raysaccept (virtual image) is imaginary accept cannot be put on screen do not credit just ‘… is not real’
1
(b) (the image) needs to fall on film / sensors / LDRs / CCDsaccept just ‘charged couples’do not credit ‘… solar cells’ do not accept virtual image cannot be stored
1
either to cause a (chemical) reaction or to be digitalisedfor credit response must be appropriate to camera type
1
object (should be) on the far side of F / the focus (from the lens)or … more than the focal length (away from the lens) allow ‘beyond the focus’
or object should be more than twice the distance / 2F (from the lens) (2 marks)or … more than twice the focal length (away from the lens) (2 marks)
1[12]
M6. (a) converging1
image1
object1
image1
object1
shorter1
(b) (i) (Earth’s) gravityaccept centripetal accept minor misspellings, however, do not credit any response which could be ‘centrifugal’
1
(ii) to(wards) (the centre of the) Earthallow inwards do not accept downwards
1
(c) (i) either
friction (force) or centripetal forceallow grip
1
between the tyres / wheels and (the surface of) the roadallow on the tyres / wheels or towards the centre of the bend / arc / circle
1
(ii) mass or speed or momentumallow weight allow velocity
1
radius / diameterdo not credit ‘curvature’ or ‘circumference’
1
(d) centripetalaccept minor misspellings (see above)
1[13]
M7. (a) (i) point where the rays crossdo not credit if ambiguous
1
(ii) converging (lens)do not accept convex
1
(b) (i) point where the rays appear to diverge fromthis should appear to be within 10mm in front of the back of the arrows on the approximate centre lineneed not be accurately constructed using a ruler
1
(ii) diverging (lens)do not accept concave
1
(c) converging1
film1
smaller than
nearer toaccept any clear indication of the response e.g. ticking, ringing, writing in after a mistake
1
(d) (i) (image) bigger than object enlargeaccept just 'made bigger'
1
(ii) it / real image can be put on a screen or real image on the opposite sideof the lens to the object
accept 'not an imaginary or virtual image'assume 'it' refers to a real imagedo not credit 'it can be seen'
1
(e) either (the converging lens is) thick in the middle thin(ner) at the edge1
thickest in the middle gains 2 marks1
or (both) sides bend outwards (1) in the middle (1)convex gains 2 markssuitable diagrams gains 2 marks
or one side bends in the middle (1) more than the other side bends inwards(in the middle) (1)
1[12]
M8. (a) (i) (angle of) refractiontake care not to credit ‘angle of reflection’
1
(ii) normaldo not credit ‘horizontal’
1
(b) either
(photographic) film
or CCD(s) (charge-coupled device(s)) / CMOS(s) (sensor(s)) / (active) pixel sensor(s)
accept ‘LDR(s)’ / ‘light dependent resistor(s)’not lux meterdo not accept light sensor(s)
1
(c) (i) convergingor ‘convex’
1
(ii) either
(0).35
or (0).4(1...)do not give any credit for an answer greater than 1or7 ÷ 20 for 1 markorclear evidence that appropriate measuring / counting, has been made for 1 mark
2
(d) otherwise it will have no effect on the light detector
or otherwise no (real) light will fall on the light detectoror ‘a virtual / imaginary image will have no effect on the light detector’allow error carried forwards for ‘light detector’allow so it can be formed on the film
1[7]
M9. (a) straight line from the tip of the object
… straight through the centre of the lens (1)
… parallel to the axis, then diverges from the lens as if from F (1)
image drawn from where these lines intersect, vertically to the axis (1)example
3
(b) any two from:
• smaller (than the object)
• (both) upright
• image is virtual / imaginary (whereas object is real)no errors carried forward from the candidate’s diagrammark first two points given
2[5]
M10. (a) converging
or convex1
(b) (principal) focus
or focal point1
(c) either (×)1.5 or (×)1½ or 150%unambiguous evidence of appropriate measurements for 1 mark only eg 4 and 6 or 8 and 12 or 0.8 and 1.2
2
(d) real rays cross to form it / formed at the intersection of real raysaccept ‘image on the opposite side of the lens to the object’accept ‘can be put onto a screen’
1[5]
M11.(a) Lens A both rays converging on other side of lens
1
Lens B both rays diverging on other side of lens1
Either refraction at both surfaces within lens or refraction at verticalline through midpoint
1
(b) (Lens B)
parallel rays (from a distant object) are focused in front of the retina1
Lens B diverges the ray before entering the eye1
hence rays appear to come from the far point of the student’s eye1
and are focused on the retina1
producing a sharp image1
(c) laser1
[9]
M12. (a) 1.59accept an answer that rounds to thisallow 1 mark for correct substitution into correct equation
ie refractive index = 2
(b) 2 lines correctly drawn from the top of the pin through the lensallow 1 mark for each
2
position of image correctimage must be upright
1[5]
M13. (a) convergingaccept convex
1
(b) 3allow 1 mark for substitution into the correct equation
ie 2
(c) biggeraccept magnified
1
upright1
virtual1
[6]
M14. (a) any two for 1 mark eachdeduct (1) from the first two marks if a ruler has not been used but the intention is clear
ray from the object's arrowhead
• through centre of lens
• parallel to the axis then, when it reaches the lens, through F on the right
• through F on the left then, when it reaches the lens parallel to the axisexample of a 4 mark response
if more than two construction lines have been drawn all must be correct to gain 2 marksconstruction lines drawn as dashed lines do not score credit
2
image shown as vertical line from axis to where their rays intersectimage need not be marked with an arrowhead but, if it is, it must be correct
1
ray direction shownonly one correct directionarrow needed but there must not be any contradiction
1
(b) any two from:
• invertedaccept ‘upside down’
• magnifiedaccept ‘bigger’
• realaccept ‘not virtual / not imaginary’one correct feature gains 1 markignore any reference to positionan incorrect feature negates a correct response
2[6]
M15. (a) (i) answer in the range 3.0 ↔ 3.1 inclusiveaccept for 13.6 ÷ 1.2 or 3.7 ÷ 1.2or 36 ÷ 12 or 37 ÷ 12or 18 ÷ 6 or 18.5 ÷ 6or 10.2 ÷ 3.4 or 102 ÷ 34or answer in the range but with a unit eg 3 cm
2
(ii) (principal) focus / focal (point(s)) / foci / focusaccept ‘focusses’accept focalsdo not accept focal length
1
(iii) at the intersection of virtual / imaginary raysor ‘where virtual / imaginary rays cross’or the rays of (real) light do not crossor the image on the same side (of the lens) as the object
or the image is drawn as a dotted lineor the image is uprightdo not accept ‘cannot be put on a screen’do not accept any response which refers to reflected rays
1
(b) (i) another correct observation about relationship between values of d (1)
(but) not the same relationship between correspondingvalues for magnification (1)example15 is three times bigger than 5 but2.0 is not three times bigger than 1.2
2
(ii) when the distance / d increases the magnification increasesor the converseaccept ‘there is a (strong) positive correlation’do not accept any response in terms of proportion / inverse proportion
1
(iii) (student has) no evidence (outside this range)accept data / results / facts for ‘evidence’
1[8]
M16. (a) (i) (concave) mirror / reflectordo not allow convex mirror / reflector
1
(ii) refraction1
(b) (i) converging1
(ii) 4allow 1 mark for correct substitutionie 20 / 5 or 4 / 1ignore any units
2[5]
M17. (a) converging (lens)
accept ‘convex (lens)’accept biconvex
1
(b) (principal) fociaccept ‘focus’ / ‘focuses’ / ‘focis’focal point(s)
1
(c) (i) formed where (real) rays (of light) intersect / meet / crossaccept rays (of light) pass through the imageaccept ‘image is on the opposite side (of the lens to the object)’accept (construction) lines cross overa response relating to a screen or similar is neutrallines are solid and not dotted is neutral
1
(ii) invertedaccept any unambiguous correct indication
1
(d) (i) smooth curve which matches the pointsjudge by eye but do not accept point to point by ruler or otherwise
1
(ii) continuous1
(iii) as distance increases, magnification decreasesaccept negative correlationa statement ‘inversely proportional’ is incorrect and limits maximum mark for this part question to 1
1
further detail eg magnification falls steeply between 40 and 50 cmormagnification begins to level out after / at 70 cm
1[8]
M18. 1.4allow 1 mark for correct substitutionie 14 ÷ 10or28 ÷ 20
[2]
M19. (a) (i) two correct rays drawn1 mark for each correct ray
• ray parallel to axis from top of object and refracted through focus and traced back beyond object
• ray through centre of lens and traced back beyond object
• ray joining top of object to focus on left of lens taken to the lens refracted parallel to axis and traced back parallel to axis beyond object
2
an arrow showing the position and correct orientation of the image for their raysto gain this mark, the arrow must go from the intersection of the traced-back rays to the axis and the image must be on the same side of the lens as the object and above the axis
1
(ii) (x) 3.0accept 3.0 to 3.5 inclusive
or
correctly calculatedallow 1 mark for correct substitution into equation using their figuresignore any units
2
(b) any two from:
in a camera the image is:
• real not virtual
• inverted and not uprightaccept upside down for inverted
• diminished and not magnifiedaccept smaller and biggeraccept converse answers but it must be clear the direction of the comparisonboth parts of each marking point are required
2[7]
M20. (a) (i) converging1
(ii) (x) 2allow 1 mark for correct substitutionie 10/5 or 20/10 or 2/1ignore any units
2
(b) decreases1
[4]
M21.(a) (i) answer in the range 3.0 ↔ 3.1 inclusiveaccept for 1 mark3.6 ÷ 1.2 or 3.7 ÷ 1.2or 36 ÷ 12 or 37 ÷ 12or 18 ÷ 6 or 18.5 ÷ 6or 10.2 ÷ 3.4 or 102 ÷ 34or answer in the range but with a unit eg 3 cm
2
(ii) (principal) focus / focal (point(s)) / foci / focusaccept ‘focusses’accept focalsdo not accept focal length
1
(iii) at the intersection of virtual / imaginary raysor ‘where virtual / imaginary rays cross’or the rays of (real) light do not crossor the image on the same side (of the lens) as the object
or the image is drawn as a dotted lineor the image is uprightdo not accept ‘cannot be put on a screen’do not accept any response which refers to reflected rays
1
(b) (i) another correct observation about relationship between values of dexample15 is three times bigger than 5 but
1
(but) not the relationship between corresponding values for magnification2.0 is not three times bigger than 1.2
1
(ii) when the distance / d increases the magnification increasesor the converseaccept ‘there is a positive correlation’do not accept any response in terms of proportion / inverse proportion
1
(iii) (student has) no evidence (outside this range)accept data / results / facts for ‘evidence’
1[8]
M22.(a) raft A is more stableno mark for identifying raft, marks for explanation
raft A has the lower centre of gravity / mass1
must be direct / implied comparison to the other raft
raft A has the wider base / is the widestaccept the barrels are spread out the mostorthe base / surface area is the largest
1
OR
raft B is less stable
raft B has the higher centre of gravity / mass (1)
raft B has the narrower base / is the widest (1)if wrong or no raft identified as being most / least stable, 1 mark maximum for BOTH correct explanations of C of G & base width
(b) any two correct construction lines:
if more than 2 construction lines treat as a list2
• line passing straight through centre of lens (& out other side)
• line travelling parallel to principal axis & then being refracted through principal focus (on RHS)
• line travelling through principal focus (on LHS) & then being refracted to be parallel to principal axis (on RHS)
inverted image drawn (with arrow) in correct location1
one arrowhead from object to image on any construction rayconflicting arrowheads negate this mark
1
(c) any two from:
• invertedaccept upside down
• real
• diminished / smallerallow ecf if ray diagram wrongly drawn but descriptions must relate to their imagea converse negates mark, eg real and virtual scores zero
2[8]
M23.(a) (i) The width of the base of the raft1
The position of the centre of mass of the raft1
(ii) Design B1
(b) (i) inverted1
real1
(ii) 0.4
allow 1 mark for correct substitution, eg (in mm)
or (in cm)
or (in m)
or (number of squares)ignore any unitsignore negative sign
2
(c) this shape ticked:
1[8]
M24.(a) (i) headlight glass and castor oilorbakeware glass and olive oil1
(ii) 1.60–1.33either order
1
(iii) lead (glass)do not accept 1.62
1
(b) (i) normal1
(ii) i correctly labelled
allow I for iaccept with or without arc
1
(iii) r correctly labelled
allow R for raccept with or without arc
1
(c) (i) 1.48(375…)1.5 scores 3 marksallow:n = 0.719 / 0.484 for 2 marksn = sin 46 / sin 29° for 1 mark
3
(ii) car headlight glassecf from (c)(i)
1[10]
M25.(a) (i)
award 1 mark for each correct label4
(ii) Marks awarded for this answer will be determined by the quality of communication (QoC) as well as the standard of the scientific response. Examiners should apply a best−fit approach to the marking.
0 marksNo relevant content.
Level 1 (1 − 2 marks)There is a basic description of at least one of either ciliary muscle or iris in terms of function.
Level 2 (3 − 4 marks)There is a clear description of the function of ciliary muscle and irisora full, detailed description of either ciliary muscle or iris.
Level 3 (5 − 6 marks)There are clear and detailed descriptions of the functions of both ciliary muscle and iris.
examples of the physics points made in the response:
Ciliary muscle:• changes the shape of the lens• relaxes to flatten lens• allowing light to be focused from distance• contracts to round lens• allowing light to be focused from close objects
Iris:• controls the amount of light entering the eye• expands / relaxes making pupil smaller• in bright light• contracts making pupil larger• in low light• helps protects the retina (in bright light)
6
(b) eyeball being too short1
(c) (i) magnified1
upright1
(ii) v = −6(cm)max 2 marks if no minus sign6(cm) gains 2 marks1/v = 1/12 − 1/4 = −1/6gains 2 marks1/12 = 1/4 + 1/vgains 1 mark−5.99(cm)using decimals gains 3 marks
3
(d) it is virtual1
[17]
M26.(a) refraction1
(b) towards the normal1
(c) (i) convex1
(ii) principal focusaccept focal point
1
(d) parallel on left1
refracted towards the normal at first surface1
refraction away from normal at second surface1
passes through or heads towards principal focus1
(e) refractive indexaccept material from which it is made
1
(radius of) curvature (of the sides)accept shape / radiusdo not accept power of lensignore thickness / length
1
(f) 5 (dioptre)1 / 0.2 gains 1 mark
0.05 gains 1 mark2
[12]
E1. Candidates fared badly with this interpretation question. While most candidates noted the eyepiece magnified very few noted that the final image was inverted and smaller for the telescope but bigger for the microscope.
E2. Optical devices were not well known with few candidates gaining full marks. There was no pattern amongst the many wrong answers offered by the candidates. There was some hedging of bets, e.g. for size “magnified/smaller”. Demagnified image was a not uncommon incorrect answer. The description of the image position was often unclear. Although not anticipated when the mark scheme was written, the position of the eye image when given as “on the retina” was credited.
E4. In part (a)(i) most candidates gained at least one mark. The most common mistakes were either to not continue the lines once the focus had been reached or to not have the focus on the axis. About half were able to name the point where the rays come together and the majority were able to name the type of lens. In (b) parts (i) and (ii) were rarely correct but most were able to name the type of lens.
In part (c) it is likely that some answers were guessed as it was rare to see a set of three correct answers.
Few candidates gained any credit in part (d). The minority who did usually knew that real images can be formed on a screen or a film whilst virtual images cannot.
E5. (a) (i) Nearly all candidates correctly recognised the lens as convex or converging.
(ii) Most candidates identified F as a focal point or focus.
(iii) Only a small minority of candidates were able to name the central horizontal line as the axis.
(iv) Some candidates seemed quite unfamiliar with the process of optical construction. Those who made a fair attempt generally secured at least three marks. The most common errors were failure to show correctly the direction of at least one ray with any contradiction, lack of accuracy and failure to show the position of the image from
the point of intersection of the virtual rays to the axis.
(v) Few candidates mentioned that a virtual image was formed as a result of the intersection of virtual rays. Many correctly noted that a virtual image cannot be projected onto a screen. Some contented themselves, but not their examiners, by simply stating ‘a virtual image is not real’.
(b) Some candidates were confident that it needed to be a real image because it needed to fall on the exposed film, but many answers were vague and generally poorly expressed. A very small minority of responses in terms of digital cameras, and similar answers, were usually worthy of credit. Many candidates knew that the object would need to be beyond the focal length, but few had sufficient understanding to state that the object would need to be at more than twice the focal length from the lens.
E6. (a) Many candidates obtained full marks in this part.
(b) (i) Most candidates correctly gave ‘gravity’ or ‘gravitational attraction’ in this part.
(ii) Not all the candidates who gave the correct answer in part (b)(i) were able to give the correct direction in this part. ‘Towards the Sun’ and ‘clockwise’ were sometimes suggested and the examiners did not consider that ‘downwards’ was an appropriate response in the context of the question.
(c) (i) ‘Friction’ was rarely suggested in this part although, if it was, then it was usually correctly located between the tyres and the road surface.
(ii) Most candidates correctly indicated that the force would be greater if the mass, or the speed, of the car was greater, but very few could express themselves correctly and describe a tighter bend. Many candidates suggested ‘angle’ or ‘curve’ for the second word and if these words convey any meaning here, it is the opposite of what might have been intended. The word ‘diameter’ or ‘radius’ was hardly ever seen.
(d) Only a very small minority gave the correct response to this part. Of the incorrect responses, ‘orbit’ was the most common.
E7. (a) In part (a)(i) most candidates were able to identify this as a converging lens and to indicate the position of the focus.
(b) Though most candidates identified this as a diverging lens, only a small minority were able to indicate the position of the focus. Many made no effort to do so and this may indicate that some candidates did not think that a diverging lens has a focus.
(c) Nearly all candidates attempted this part and followed the instructions. Some gained all four marks.
(d) Attempts at explaining the word magnified were much more successful than attempts atreal. The many, wildly incorrect responses indicated that few had been able to find any clues in the artwork.
(e) Only a minority of candidates had the confidence to simply state that the converging lens would be convex. However, ‘thicker in the middle and thinner at the edges’ was a fairly popular correct answer. Some candidates were not assisted by their limited ability to communicate clearly. A minority claimed that if only one lens was a converging lens then all the others would be the same. This is not correct; each lens in the box might be a different shape.
E8. Foundation Tier
(a) (i) A third of candidates identified the angle of refraction correctly.
(ii) A quarter of candidates could name the dash line as the normal.
(b) A small minority of candidates answered in terms of a digital camera. Only a few of the candidates identified any king of light detecting device eg film.
(c) (i) About half of candidates recognised that this is a converging or convex lens.
(ii) The diagram had been reduced to fit the page but, regrettably, the dimension 1.4cm had not been altered. However no candidate was disadvantaged. This question was answered well with 50 % of candidates gaining at least 1 mark. Numerically correct answers obtained by measuring or by counting or by using the dimension in some appropriate combination were awarded both marks. Where, for example, a correct method and calculation had been employed but a small mistake had been made, eg the object had been miscounted as 21 small squares rather than 20, then one mark was scored.
(d) Very few candidates related the formation of a real image to the necessity for light to fall on a light detector.
Higher Tier
(a) (i)(ii) Most candidates knew that the angle is the angle of refraction and that the dotted line is the normal.
(b) About a half of candidates suggested photographic film though some had it as photographic paper; LDRs were sometimes proposed but there were few correct references to the light sensors in digital cameras.
(c) (i) A high percentage of candidates recognised that this is a converging or convex lens.
(ii) The diagram had been reduced to fit the page but, regrettably, the dimensions 1.4cm had not been altered. However no candidate was disadvantaged. Numerically correct answers obtained by measuring or by counting or by using the dimension in
some appropriate combination were awarded both marks. Where, for example, a correct method and calculation had been used but a minor mistake had been made, eg the object had been miscounted as 21 small squares rather than 20, then one mark was scored.
(d) Few candidates seemed to understand that, in order to have an effect on the light sensor; light must fall on it.
E9. (a) There were many examples of incorrect constructions. Only a minority of candidates drew two straight lines; one from the top of the object which continued through the centre of the lens and the other parallel to the principal axis which continued as if from F when it reached the lens. However, some of those candidates who got this far went on to secure their third mark by showing the image located vertically with the intersection of these lines marking the top of the image.
(b) Adjectives and features which may be used to describe images were employed fairly randomly. Diminished/smaller, erect/upright, and virtual/imaginary are correct but only about one quarter of the candidates secured two marks.
E10. (a) Usually the lens was incorrectly identified as a diverging or concave lens rather than as a converging or convex lens.
(b) Only about a quarter of candidates recognised that the point is a principal focus or a (focal) point.
(c) More able candidates were able to take appropriate values from the diagram and to calculate the magnification.
(d) A very small minority of candidates gained the mark because they stated that the image could be put on a screen. No one referred to a correct diagram and stated that the image is real because it is formed where real rays cross.
E14. (a) A significant number of candidates (approximately a quarter) failed to score any marks, with an equal number scoring all four. Many candidates, having completed the ray diagram, successfully omitted any arrows showing direction. It was perhaps fortunate that marks were not awarded for the accuracy of the diagram as this was often poor. Independent marks meant that candidates were able to score one or two marks for image
placement or ray direction even when their rays were more suitable for a mirror instead of the lens shown.
(b) Surprisingly just under half of candidates scored both marks. Many candidates lost credit by producing a long list of features that were often contradictory.
E15. (a) (i) Just over half of the candidates were able to work out the magnification.
(ii) Just over half of the candidates could name the principal focus.
(iii) Candidates had difficulty explaining how the diagram showed that the image was virtual, many candidates stated it was behind or in front of the lens without reference to the object and a number of answers mentioned reflected rays and /or mirrors.
(b) (i) Half of the candidates gave a correct explanation. A significant number of candidates appear to not understand the term ‘directly proportional’ and hence gave incorrect answers.
(ii) & (iii) Only a minority of candidates gave the correct answer to why a conclusion could not be given outside the range of the experiment.
E16. (a) (i) Nearly half of candidates correctly identified the mirror/reflector. A few candidates lost the mark by describing it as convex but the most common mistake was to call it a lens.
(ii) Just over half of candidates could correctly name the process as refraction. The most common error was to call it reflection. There were very few alternatives.
(b) (i) Two thirds of candidates knew that the diagram showed a converging lens.
(ii) Nearly three quarters of candidates obtained both marks for the calculation. However, it was disappointing to see how many candidates gave a unit, usually cm, for the magnification. Very few candidates made no attempt to answer this part question.
E17. (a) Just over half of the candidates could identify the type of lens shown in the diagram.
(b) Just over three-fifths of candidates were able to correctly name the points labelled F.
(c) (i) Explaining how a diagram shows whether an image is real or virtual continues to be a problem. Many candidates mention ‘in front’ or ‘behind’ the lens without identifying what they mean. Candidates need to state whether it is the same or opposite side of the lens to the object. A number of candidates negated any answer by mentioning reflections and / or mirrors.
(ii) Although just over three quarters of candidates scored this mark, it is surprising that most of the remainder thought that the image was upright.
(d) (i) The response to drawing the line of best fit on given plotted points was extremely disappointing. Many candidates ignored the point at (40,2.9). The majority of candidates tried to draw a straight line through an obvious curve while others joined up the points with a ruler. Only a third of candidates drew an acceptable curve through the points.
(ii) Just over two-thirds of candidates gave the correct answer to this part question.
(iii) A large majority of candidates managed to give the basic relationship linking magnification and distance but a very small number of candidates gained the second mark by giving more detail.
E18. Just over half of the candidates, who read the diagram correctly had no difficulty with this question and scored full marks. However, a substantial number of candidates made errors in taking the measurements.
It was disappointing that, once again, some candidates added a unit to the magnification.
E19. (a) (i) Although over 37% of candidates gained all three marks, 50% of candidates scored zero!Those scoring zero clearly had no idea how to draw a ray diagram for a converging lens used as a magnifying glass.
(ii) Many candidates knew how to use the magnification equation and even candidates that had not scored any marks in part (a)(i) were able to gain these two marks through ‘error carried forward’.
(b) Again poorly answered with 50% of candidates scoring zero. Many candidates failed to gain any marks as there was no comparison made between the camera and the
magnifying glass.
E20. (a) (i) Nearly 62% of candidates knew that the diagram showed a converging lens.
(ii) Those candidates able to read the diagram found that the calculation very simple. However a significant proportion of candidates multiplied their two numbers rather than divide them and therefore gained no marks, this was despite being given the equation.
(b) Although the information required was provided in the diagram, only 58% of candidates correctly identified the effect on the image of moving the object closer to the lens.
E21.(a) (i) Students did not read the diagram carefully enough so that just over half of students achieved full marks on the calculation and many scored zero.
(ii) The majority of the students were able to name the points.
(iii) Less than a quarter of the students could explain how the diagram showed that the image was virtual. Students described the image as being 'in front of', 'behind', ' to the left of' or 'to the right of' the lens without any reference to the position of the object. These statements are therefore meaningless.
(b) (i) Many students relied too much on the information in the stem of the question and did not therefore give enough further detail to gain both marks. Just over half of the students gained at least one mark.
(ii) Just over half of the students gave the correct conclusion many of the others restated the original incorrect conclusion or simply stated that it was not correct.
(iii) The majority of students were unable to explain why a conclusion could not be made outside the range of the experiment.
E22.(a) The term “centre of mass” was well generally well known in this question, with most candidates gaining both marks for this question.
(b) Only a quarter of candidates gained full marks for this ray diagram. A further third gained 3 marks, the most common mistake being a failure to put an arrow on any of the rays.
(c) The majority of candidates were able to identify the nature of the image correctly with two descriptions.
E23.(a) The vast majority of candidates gained all the marks in (a)(i) and (a)(ii).
(b) (i) About one third of the candidates correctly identified two words to describe the image. About one half of candidates could identify one description correctly.
(ii) About half of the candidates scored both marks for correctly calculating the magnification of the image. A number did not attempt this calculation.
(c) Most candidates correctly identified the concave lens.
E24.This question was easily the best answered question on the paper. About nine-tenths of students scored full marks on every part which included the need to look up the sines of two angles and calculate a value for refractive index.
(a) (i) Most students were able to identify from the table a type of glass and liquid where the glass would seem to disappear.
(ii) Most students were able to identify the range from the figures given in the table.
(iii) Almost all students answered this question correctly.
(b) (i) Most students were able to correctly name the dashed line as the ‘normal’.
(ii) Curiously the lowest scoring parts were those where the angles of incidence and refraction had to be labelled on a diagram.
(iii) Curiously the lowest scoring parts were those where the angles of incidence and refraction had to be labelled on a diagram.
(c) (i) A few students did not use sines in this part and those who rounded their answers for refractive index from 1.48 to 1.5 disadvantaged themselves when referring back to the values in the table.
(ii) A few students did not use sines in (i) and those who rounded their answers for refractive index from 1.48 to 1.5 disadvantaged themselves when referring back to the values in the table.
E25.(a) (i) Nearly three-quarters of students could successfully identify parts of the human eye. Almost all students gained at least one mark.
(ii) In the Quality of Communication question most students were able to describe the functions of the ciliary muscle and the iris.
A few students linked the action of the ciliary muscle to an effect on the iris rather than the lens. There was some confusion about how the change in shape of the lens allowed objects at different distances to be focussed often because the terms ‘fatten’ and flatten’ were used. Some students are not clear concerning the effects of relaxing and contracting on the size of the lens and the pupil.
A quarter of students scored four or more marks out of six.
(b) Three-quarters of students knew that long sight can be caused by the eyeball being too short.
(c) (i) Less than three-quarters of students identified the image in the ray diagram as being
magnified and upright.
(ii) More than half of the students gained full marks for a calculation using the lens formula that required a minus sign in the answer. Most of the remaining students forgot to invert the value for the final answer.
(d) Most students knew that a minus sign meant that the image was virtual.
