2011 SAC 1 - test · Web viewTest Fields - Solutions Reading Time: 10 minutes Writing time: 60...

1 12PHYSICS FIELDS Solutions

VICTORIAN CERTIFICATE OF EDUCATION

2017

NAME:_________________________ TEACHER: ________________________

PHYSICS

School Assessed Coursework: Test

Fields - Solutions

Reading Time: 10 minutesWriting time: 60 minutes

QUESTION AND ANSWER BOOK

Section Number ofquestions

Number of questionsto be answered

Number of marks

A 6 6 39

Students are permitted to bring into the examination room: pens, pencils, highlighters, erasers, sharpeners, rulers, up to two pages (one A4 sheet) of pre-written notes (typed or handwritten) and one scientific calculator.

Students are NOT permitted to bring into the examination room: blank sheets of paper and/or white out liquid/tape.

Materials Supplied Question and Answer book of 11 pages. A formula sheet.

Instructions Write your student name and teacher name in the space provided above on this

page. Unless otherwise indicated, the diagrams in this book are not drawn to scale. All written responses must be in English.

At the end of the examination Close your Question and Answer booklet and ensure your name and your teacher’s

name is clearly printed on the front cover.

Students are NOT permitted to bring mobile phones and/or any other unauthorised electronic devices into the examination room.


Area of study – Fields

Question 1 (6 marks)In 1820, Hans Christian Oerstead discovered that a current carrying wire would produce a magnetic field. a. Draw 3 magnetic field lines around the current carrying wire. 1 mark

In 1824, William Sturgeon invented an electromagnet by coiling a current carrying wire around a piece of soft iron.

b. Draw 5 magnetic field line around the electromagnet.

Instructions

Answer all questions in the spaces provided. Use black or blue pen.Where an answer box has a unit printed in it, give your answer in that unit. You should take the value of g to be 9.8 m s-2.Where answer boxes have been provided, write your final answer in the box.In questions where more than one mark is available, appropriate working should be shown.Unless otherwise indicated, diagrams are not drawn to scale.


At point P the magnetic field provided by the solenoid is twice the strength of that of the Earth. The

strength of the magnetic field of the Earth is 50 μT.

c. Calculate the magnitude and direction of the resultant magnetic field at point P. On the diagram, illustrate the resultant magnetic field at P with an arrow.

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Magnitude Direction

N

P


Question 2 (7 marks)

Consider the two charged plates that are separated by small distance of 2.3 cm. The potential difference across the battery is 9.0 V

a. Draw 4 electric field lines between the two plates. 1 mark

b. Calculate the magnitude of the electric field between the plates. 1 mark

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An electron is accelerated from rest from one plate to the other.

c. Calculate the magnitude of the change in electrons kinetic energy as it traverses between the plates.

2 marks

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N C-1

J

2.3 cm

9 V


Kes says that the force on the electron is constant as it moves between the plates but her friend Nelix argues that force on the on electron increases as it accelerates.

d. Who is correct, Kes or Nelix? Explain your response. 3 marks

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Kes is correct. The electric field between the plates is uniform. The F = qE, since q and E are constant, the force on the proton is

also constant.



A proton of mass 1.67 × 10-27 kg moving at 2.5 × 106 m s-1. The proton moves into a magnetic field and experiences a force of 2.0 × 10-14 N.

a. Which direction is the force on the proton as it enters the magnetic field? 1 mark

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b. Calculate the magnitude of the magnetic field. 2 marks

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c. Calculate the radius of the protons path in the magnetic field.

2 marks

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50 mT

52 cm

. . . . . . .

. . . . . . .. . . . . . . .. . . . . .

2.5 × 106 m s-1

Down



The gravitational field at the International Space Station (ISS) is 8.7 N kg-1.

a. Calculate the altitude of the ISS 3 marks

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b. Calculate the speed of the ISS. 3 marks

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7680 m s-1

Earth

412 km


c. Calculate the period of ISS’s orbit.

3 marks

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1.52 hours

s


Question 5 (6 marks)In the book The Martian, written by Andy Weir, the protagonist, Mark Watney (m = 55 kg), has been stranded on the surface of Mars and must use a rocket, of mass 800 kg, to project himself into space in order to be rescued by a crew in orbiting Mars. Mars has a radius of 3.4 x 106 m and he must get to a height above the surface of 3.6 x 106 m in order to be rescued.

a. Calculate the amount of energy required to lift Watney and his rocket from the Mars’ surface to an altitude of 3.6 x 106 m.

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5.58 × 109 J

A1 A2 A3 A4


The NASA team informs Watney that the rocket can do 4.5 x 109 J of work, and he must strip the rocket of any unnecessary mass to ensure he makes the required height.

b. How much rocket mass must Watney leave behind to be sure he makes the required height above Mars’ surface?

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176 kg


Question 6 (6 marks)In 1821, Michael Faraday created the first electric motor. It consisted of a wire that hung in a liquid mercury which rotated around a permanent magnet. In 1838, Moritz Von Jacobi created an electric motor that drove a boat with 14 people across a river. The diagram shows a DC motor.

a. From the point of view shown in the diagram, does the coil rotate clockwise or anti-clockwise? Explain.

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b. Explain how the split ring commutator keeps the motor rotating in one direction.

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END OF OUTCOME 1

NS A

B C

D

Anticlockwise The current flows around the coil D, C, B, A and the magnetic

field is to the left. Using RH rule, the force on CD is up and the force and AB is

down.

The split ring commutator changes the direction of the current in the coil every half turn.

The forces on the side AB and DC change direction every half turn.

The torque on the coil remains in the same direction.

2011 SAC 1 - test · Web viewTest Fields - Solutions Reading Time: 10 minutes Writing time: 60...

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