SKEMA KEM FIZIK
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Transcript of SKEMA KEM FIZIK
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Question Mark Scheme Marks
1 (a)
(b)
(c) (i)
(ii)
Ratchet
To prevent too much pressure being exerted on the object.
Positive Zero Error
2.80 0.02 // 2.78 mm
1
1
1
1
2(a)
(b)(i)
(ii)
c(i)
(ii)
Work = Force X displacement /distance in specific direction
W = F X S
= 220 X 0.5
= 110 J
W = mgh
= 20X10X0.5
= 100 J
Work done in (b)(i) > (b)(ii)
More work is used to overcome the friction // Lebih banyak keja dilakukan untuk mengatasi daya geseran
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1
1
1
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1
3(a)
(b)(i)
(ii)
(iii)
(iv)
(v)
(c)(i)
(c)(ii)
Force
Area
Same
Diagram 5.1 more sinking // Diagram 5.1>
Area contact Diagram 5.1 is larger //more // >
Depth of sinking increase, pressure increases // directly proportional to
pressure // use symbol
Pressure
Increases
Force /weight increase, pressure increases // Force /weight directly
proportional to pressure // use symbol
1
1
1
1
1
1
1
1
4(a)
(b)
(c)
Latent heat of fusion Haba pendam pelakuran
Heat energy absorb used to break the bond between the molecules Haba yang diserap digunakan untuk memutuskan ikatan antara molekul
Q = mcQ
= 1.0 X 4 200 X 100
= 420 000 J
1
1
1
1
-
(d)
1
1
1
5(a)(i)
(a)(ii)
(b)(i)
(c)(i)
State the correct meaning of heat;
A form of energy //
A form of energy that flows from hot to cold object//
A form of energy due to change in temperature
Explain the reasons by making relationship between large mass and the
amount of heat transferred correctly;
M1: The large mass of hot water has a large heat capacity //
It will transferred large amount of heat from the hot water to the
noodles.
M2: This shorten/reduce the time needed to cook the noodles.
Shows the calculation and substitution of m and correctly Q cool water absorbed = Q hot water released
m1 c1 ( - 1) = m2 c2 ( 2 - )
2 ( - 30) = 9 (95 - )
Shows the correct answer and unit
= 83.18 C
c = Pt
m
c cer = (180) ( 10x60)
( 2) (60)
= 900 J kg C-1
c glass = (70 ) ( 15x60)
( 2) (60)
= 525 J kg C-1
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1
1
1
1
1
1
1
For the
Cglass, mark
is given for
either correct
calculation
or correct
answer
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(c)(ii)
(d)(i)
(d)(ii)
States the correct choice Ceramic
States the correct reason High specific heat capacity will maintain heat for a longer period.
M1: Land has a smaller specific heat capacity than sea //
Land faster increase in temperature // Land is warmer than the sea
M2: Air above the land is heated up and rises
M3: Cooler air from the sea moves towards the land
Or diagram
M1 Label Sea(cold), Land (Hot)
M2 Show Hot air on land rises up
M3 Show Cold air moves towards the sea
Sea breeze
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1
1
1
1
1
6(a)
State the meaning offocul point correctly
A point where parallel ray converge/focused/diverge//
midpoint between P and C
OR DIAGRAM CURVE MIRROR/LENS
1
-
(b)
(c)(i)
(c)(ii)
(d)(i)
(d)(ii)
(e)
Draw the ray diagram correctly
1st a ray from object parallel to its principal axis,
2nd
a straight line/ray from object passes C to mirror
3rd
extrapolation of both rays to form the image and show the image
Complete the ray path correctly 1
st ray reflected- arah tak perlu tanda
- Mana-mana arah di depan cermin
dalam julat A ke B
2nd
ada normal line
Reflected ray between A and B
i = r
State the light phenomenon correctly
Reflection pantulan
Suggest the position of the bulb correctly
Focul point/focul length/F/f
Suggest the curvature correctly
Increase the curvature/decrerase radius/decrease focul length/more
curve/bigger/wider/parabolic/more/more circular (b.o.d)
Suggest one method correctly
Higher power bulb /increase power/increase power supply/increase
battery/more battery/more current/more voltage/increase number of coil of
filament / smooth surface reflector/shinny surface reflector/mirror as
reflector/clean the glass cover /take out the glass cover/krypton bulb/ LED
bulb
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1
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1
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1
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7.(a)
(b)
(c)(i)
(c)(ii)
(c)(iii)
(d)
The angle of the incidence when the angle of refraction is 90. Sudut tuju apabila sudut biasan ialah 90.
The angle of incidence is zero which is parallel to normal causing the angle of
reflection to be zero. Sudut tuju ialah sifar yang mana selari dengan normal, menyebabkan sudut pantulan ialah sifar.
Prism / Prisma P
Increase the angle of incidence (more than 45) Tambah sudut tuju (lebih daripada 45)
Prism / Prisma Q
Reduce the angle of incidence (less than 45) Kurangkan sudut tuju (kurang daripada 45)
Glass is denser than air. Kaca lebih tumpat daripada udara.
Diagram 5.1 - Refracted away from the normal Rajah 5.1 - Dibias jauh daripada normal
Diagram 5.2 - Totally reflected Rajah 5.2 - Dipantulkan sepenuhnya
Total internal reflection Pantulan dalam penuh
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1
1
1
1
1
1
1
8(a)(i)
(ii)
(iii)
(iv)
(v)
(b)(i)
(b)(ii)
Compare the distance between two consecutive loud sour X correctly.
The distance between two consecutive loud sound in diagram 6.1 is further/
longer/bigqer // (vise versa)
(boleh guna simbol)
Compare the distance between the two loudspeaker, a correctly.
The distance, a in diagram 6.1 is shorter/nearer/closer/ smaller // (vise versa)
(boleh guna simbol)
State the relationship
As, a increase, x decrease (vise-versa)// a, is inversely proportional to x
// a 1/x
State the physical quatity correctly
Distance between the loudspeakers and line interference pattern / D /
wave length / / f
Name the physical phenomenon correctly
Interference
State the meaning of frequency correctly
Number of complete oscillation / vibration / cycle / wave per second /
minute / per unit time
State the change in the diatance correctly
Decreases // shorter // reduce
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1
1
1
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1
1
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(b)(iii)
State the reason correctly
As the frequency increase the wavelength decreases // wavelength
inversely proportional to frequency //(symbol) 1/f // x // f 1/
1
9(a) (i)
(ii)
(b)
(c) (i)
(c)(ii)
(d)(i)
(ii)
Step-down transformer Transformer injak turun
Magnetise and demagnetise to reduce the loss of energy. Memagnet dan menyahmagnet untuk mengurangkan kehilangan tenaga.
Ns = Vs
Np Ns
Ns = 6
1000 240
Ns = 25 turns
Output power = input power X 0.75
= 0.1 X 240 X 0.75
= 18 W
Use thicker wire for the coil / Use laminated iron core. Guna wayar yang lebih untuk teras itu / Guna teras besi lembut berlamina.
Because alternating current (a.c) is supplied to the television. Kerana arus ulang alik dibekalkan kepada televisyen itu.
Diode. Connect four diodes to form a bridge rectifier. Diod. Sambungkan empat diod untuk membentuk jambatan rektifier.
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1
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1
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1
1
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10(a)
(b)
(c)
(d)
State the meaning of cathode ray correctly
high speed electron // electron that move / travel // electron beam/stream/ray //
fast moving electron // electron high kinetic energy ' _
Explain the formation correctly M1 : electron hit the screen
M2 : the kinetic energy change to light_
Shows a correct substitution
2 x 2 // 2 + 2
Answer with correctly unit
4V
Sketch the output signal correctly
M1 : a vertical line
M2: lenght of the line is 6 division // Vpp = 6 divisions
11(a)
b (i)
Bahan yang mempunyai kekonduksian elektrik di antara konduktor dan
penebat.
Rajah 6.1, mentol menyala // Rajah 6.2 mentol tidak menyala
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b (ii)
b(iii)
b(iv)
b (v)
c(i)
(c)(ii)
Arus dalam Rajah 6.1> 6.2
Rajah 6.1 sambungan diod pincang depan//
Rajah 6.2 sambungan diod pincang songsang
Apabila diod dalam sambungan pincang depan, mentol akan menyala.
Diod
Semasa separuh kitaran pertama, diod pincang songsang, arus tidak mengalir.
Semasa separuh kitaran kedua diod pancang ke depan, arus mengalir.
12(a)(i)
(ii)
(b)(i)
(ii)
(iii)
Fleming's left hand rule Petua tangan kiri Fleming
To produce a constant force on the copper wire. Untuk menghasilkan daya yang seragam ke atas dawai kuprum.
Component: Mirror behind the needle pointer. Komponen: Cermin di belakang jarum penunjuk.
Explanation: To avoid parallax error by letting the users to take the reading
when the image of pointer coincides with the actual pointer. Penerangan: Untuk mengelakkan ralai paralaks dengan membenarkan pengguna
mengambil bacaan apabila imej penunjuk bertindih dengan penunjuk sebenar.
13.(a)
NOT Gate
~
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(b)
(c)
(d)
Output X
0
1
0
0
To switch oil the security lamp that requires current that is higher than the
output current from the AND gate. Untuk menghidupkan lampu keselamatan yang memerlukan arus yang lebih tinggi
daripada arus output yang dihasilkan oleh get DAN.
14(a) State one characteristic of beta particle correctly Negatively charge // bending towards positive plate / bending in
electric/ magnetic field // electron // charge //small low/
light mass// medium penetrating / ionizing power //medium speed //medium
range in air //can be stopped by Al // negative one proton number
Draw the horizontal or vertical lines on the graph correctly.
State the value of half-life correctly
12 1 (11-13 hours)
State the reason correctly
-
// 3 X(12 hours) // 3 (T ) //
State the time correctly//Answer correctly without units.
3 X (12 hours) = 36 hours // any answer from 33 - 39 hours // (1980 -2340)
minutes
15(a)
(b)(i)
(ii)
(iii)
(c)
(d)(i)
(d)(ii)
(e)
Radioisotope is an unstable nucleus that emits radiation (decay) to become
more stable. Radioisotop ialah nucleus yang tidak stabil yang memancarkan sinaran (mereput)
untuk menjadi nukleus yang lebih stabil.
Has long half-life Mempunyai setengah hayat yang panjang Reason //Alasan: To save cost Untuk menjimatkan kos
Beta particle Zarah beta Reason: Has penetrating power that is enough to penetrate the cardboard sheet
Therefore, overexpose will not occur. Alasan: Mempunyai kuasa penembusan yang mampu menembusi kepingan kadbod.
Oleh itu, pendedahan terlampau tidak akan berlaku.
Solid Pepejal Reason: Can be handled easily // easy to carry
Alasan: Senang dikendalikan // senang dibawa
Strontium-90
Decreases / Berkurang
When the sheet is too thick, the detector will receive lower counts. As a result,
the computer will make proper adjustment to make the roller to increase
compression on the sheet.
Apabila kepingan terlampau tebal, pengesan akan menerima bacaan yang lebih
rendah. Kesannya, komputer akan membuat penyelarasan yang sesuai untuk
membuatkan penggelek meningkatkan mampatan terhadap kepingan itu.
Time taken / Masa yang diambil
= 4 X T
= 4 X 5.27 years / tahun = 21.08 years / tahun
16(a)
(b)
An electromagnet is a conductor which can produce magnetic field
- The number of turns of the coils in Diagram 10.2 is more than in Diagram 10.1
- Bilangan lilitan gegelung dalam Rajah 10.2 lebih banyak berbanding rajah 10.1
-
(c)
- More pin are attracted to the soft iron core in Diagram 10.2 than in Diagram 10.1
- Lebih banyak pin yang tertarik pada besi teras lembut didalam rajah 10.2 berbanding Rajah 10.1
- Current in Diagram 10.1 is same/equal to Diagram 10.2 - Arus didalam Rajah 10.1 adalah sama dengan Rajah 10.2
- When the number of turn is increase, the higher the number of pin attracted - Apabila bilangan lilitan bertambah, bilangan pin yang tertarik juga
bertambah/meningkat
- When the number of turn in the solenoid is increase, the stronger the magnetic field
Apabila bilangan lilitan pada solenoid bertambah, semakin kuat medan magnet.
- The two aluminium rods attract - Dua rod aluminium tertarik
- Current flowing through the alluminium rod are in the same direction//shows in the diagram the direction is same.
- Arus yang mengalir dalam rod aluminium adalah sama arah//tunjukkan arah dalam rajah
- The magnetic fields produced by the current in them will combine to form a resultant/catapult field//show in the diagram the magnetic field
in opposite direction between the currents - Medan magnet dihasilkan oleh arus yang bergabung seterusnya membentuk
medan katapult// Tunjukkan pada Rajah medan magnet dalam arah berbeza
dengan arus
- A weak magnetic field is produced in a region between the aluminium rod because the magnetic field lines are in opposite direction// diagram
shows forces are inwards. Medan magnet yang lemah dihasilkan dikawasan diantara rod aluminium
sebab garis medan magnet berada dalam arah bertentangan//Rajah
menunjukkan daya
Modification Reason
1.The type of coiled wire
Use cooper wire Guna wayar kuprum
1.Very good conductor
//resistance is low Konduktor yang baik//rintangan
rendah
2.The thickness of the coiled 2.To reduce the resistance
-
wire
Use thicker wire Guna wayar tebal
Untuk mengurangkan rintangan
3. the type of the core
Use soft iron core Guna teras besi lembut
3.easy to magnetised and
demagnetized Mudah mengalami magnet dan
nyahmagnet
4. characteristic of the core
Use laminated core Guna teras berlamina
4. To avoid the eddy current in
the core Untuk mengelakkan arus pusar di
dalam teras besi
5.the arrangement of the
primary and the secondary coils
Winding the secondary coil on
top of the primary Gelungkan lilitan sekunder diatas
lilitan primer
5. to reduce the leakage of
magnetic flux Untuk mengurangkan kebocoran
fluks magnet
17(a)
(b)
(c)
When force is applied to an enclosed fluid, the pressure produced is
transmitted equally throughout the enclosed fluid
-When a small force is applied to piston A, pressure
is produced.
-The pressure is transmitted equally throughout the whole
liquid
-When the pressure exerted on surface area of the large
Piston B, a bigger force is produced to lift up the load
-The force is bigger due to the bigger surface area //F A
Characteristics Reason
1. The ratio of surface area
of the large piston to the
small piston
Large // big
To produce a bigger output force
2. Type of liquid used oil
Does not evaporate easily // does
not produce bubbles //
High viscosity
3. Material used for the
transmission pipe
steel
Strong //Not easy to break // long
lasting
4.Size of liquid reservoir
Big // large // larger
To occupy a large amount of
hydraulic liquid // Able to lift load
higher //
Avoid spill over
Chosen: Hydraulic jack R because it has the ratio of surface
area of the large piston to the small
piston is big, the ratio of surface
area of the large piston to the small
piston is oil, the ratio of surface
area of the large piston to the small
piston is steel and the ratio of
surface area of the large piston to
the small piston is large.
-
(d)(i)
(ii)
(iii)
P = F = 10 = 2500 Pa
A 0.004
FY = 2500 x 0.2
= 500 N
dy = 0.004 x 0.3
0.2
= 0.006 m
18(a)
Electrical energy light energy
1 1
1. When an a.c. voltage is supplied to the primary coil, the soft - iron core is magnetized
2. The magnet produced varies in magnitude and direction
3. This causes a changing magnetic flux to pass through the secondary coil
4. Induced e.m.f across the secondary coil is produced.
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1
1
1
4
Characteristic Reason
Soft iron core Easy to magnetized and
demagnetised
Laminated Less eddy current/ reduce energy
lost
Thick wire
Reduce the resistance/more current
Copper wire Low resistance/ reduce the lost of
heat
Chosen: Q
Because it has Soft iron core,
Laminated , thick wire, Copper
wire
2
2
2
2
2
10
12 V 1
5
Np = Vp
Ns Vs
Np = 240 x 200
12
= 4000
1
1
Efficiency = Po x 100
Pi
= 240 x 0.2 x 100
48
= 100 %
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1
19
(a)(ii)
npn
M1: In bright day, the light-dependent resistor(LDR) has a very low
resistance.
M2: Therefore the potential diference across LDR is low
M3: The potential difference across resistor R is high.
M4: The base current flow and cause a large collector current flows. The
bulb lights up
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1
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1
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(c)(i)
(c)(ii)
(c)(iii)
(d)
1,2
3,4
5,6
7,8
9,10
V X-Z = 6 V
V X-Y = 6 -1 = 5 V
VRR
RV
NM
MM 6
VR
R
M
M 61000
5
5RM+ 5000 = 6RM
RM= 5000
Characteristics Reason
1. The position of the LDR
LDR is connected at base circuit
When intensity of light is
low / dark, resistance of
LDR increases / so Vbase is
large / transistor switched
on
2. The connection of the batteries
Terminal positive of batteries is
connected to collector
So that the transistor is
forward biased
3. The arrangement of the street
lights circuit
Bulbs are arranged in parallel
circuit
All bulbs are connected to
voltage supply of 95V
4. The use of a relay switch in the
circuit
Relay switch is used
So that the secondary
circuit will switch on // So
that the electromagnet will
switch on the secondary
circuit
Choosen: R
because it LDR is
connected at base circuit,
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1
2
2
2
2
2
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SELAMAT MAJU JAYA SPM 2014
terminal positive of
batteries is connected to
collector; bulbs are
arranged in parallel circuit
and relay switch is used.