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Index Number :

MINISTRY OF EDUCATION

FIJI SEVENTH FORM CERTIFICATE EXAMINATION 2013

PHYSICS PAPER 2

QUESTION AND ANSWER BOOK

Time Allowed: One Hour

(An extra ten minutes is allowed for reading this paper.)

HAND IN THIS QUESTION AND ANSWER BOOK TO THE SUPERVISOR BEFORE YOU LEAVE THE EXAMINATION ROOM.

INSTRUCTIONS

1. Write your Index Number at the top of this page and inside the back flap of this Question and

Answer Book.

2. Write your answer to each question in the space provided in this book.

3. Answer all the questions with a blue or black ballpoint or ink pen. Do not use red ink. Use a pencil only for drawings.

4. If you use extra sheets of paper, be sure to write clearly the question number(s) being answered and to tie each sheet securely in this book in the appropriate places.

5. You may use a calculator, provided it is silent, battery-operated and non-programmable.

6. There are eight questions altogether in this paper. All the questions are compulsory and each one is worth five marks.

7. Spend approximately seven minutes on each question.

8. Before handing in this Question and Answer Book, make sure that your Index Number is at the top of this page, inside the back flap and on any extra sheet(s) of paper you may have used.

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2.

QUESTION 1

(a) To investigate the relationship between the length (l) of a simple pendulum and its period (t), a group of Form 7 students discovered that l = atb. To determine the value of b, the students had to plot a graph of log l against log t.

(i) How would the value of b be determined from the graph?

_______________________________________________________________________

_______________________________________________________________________ (1 mark)

(ii) If the measurements were plotted directly onto a log/log graph paper, how would the students have obtained the value for b?

_______________________________________________________________________

_______________________________________________________________________ (1 mark)

(b) A group of students measured the length, width and thickness of a microscope slide and recorded them as:

Length = (6.2 ± 0.1) cm

Width = (1.7 ± 0.1) cm

Thickness = (1.2 ± 0.1) mm

(i) What is the thickness of the slide in centimetres, including its uncertainties?

_______________________________________________________________________

_______________________________________________________________________ (1 mark)

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3.

(ii) Calculate the volume of the microscope slide with its appropriate uncertainty.

_______________________________________________________________________

_______________________________________________________________________ (2 marks)

QUESTION 2

(a) A mass, m hangs at rest on a coiled spring. A vertical force, F is applied to the mass and an extension, x is produced as illustrated by the graph.

(i) What constant will be used to convert mass to force?

_______________________________________________________________________

(1 mark)

(ii) What does the gradient of the graph represent?

_______________________________________________________________________ (1 mark)

Turn Over 5

Force (N)

2 3

1

0

2.0

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4.

(iii) Calculate the work done in extending the spring between 1 m and 2 m.

_______________________________________________________________________

(1 mark)

(b) You have been instructed to determine the gravitational field strength by considering the acceleration of a mass in the earth’s gravitational field.

You have been supplied with the following materials:

ticker timer, ticker-timer tape, trolley, five-100 g masses, pulley, scale pan, string

Sketch the experimental set-up for this investigation.

Label your diagram clearly.

(2 marks)

© MINISTRY OF EDUCATION, FSFCE 2013: PHYSICS.

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5.

QUESTION 3

Shown below is an experimental set-up to introduce the idea of rotational motion to a moving object and to measure the rotational energy of a cylinder.

(i) Why is it necessary to compensate for friction in this experiment?

_____________________________________________________________________________

(1 mark)

(ii) Describe the procedure followed to compensate for friction.

_____________________________________________________________________________

(2 marks)

(iii) Identify the two forms of kinetic energy gained by the cylinder.

_____________________________________________________________________________

(1 mark)

(iv) If the cylinder bracket has mass, M and inertia, I and the mass in the scale pan is m, write down the expression for their total kinetic energy in terms of M, I, m, v, and ω_.

_____________________________________________________________________________

(1 mark)

Turn Over 5

Ticker timer _{Cylinder (M)}

Pulley

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6.

QUESTION 4

(a) In the experiment to measure the electric field in conductors, a composite wire AB made from wires x and y was used as in the circuit diagram given below. The potential differences (V) at different points along the composite wire were measured against the length (l).

(i) On the axes given below, sketch the graph expected if the potential difference, V is plotted against the length, l for various points between A and B.

(1 mark)

(ii) From the graph that you expect to get, how can you tell which conductor

x or y has the stronger electric field in it?

_______________________________________________________________________

(1 mark)

(iii) Would the voltmeter give a zero reading along composite wire AB? Explain briefly.

_______________________________________________________________________

(1 mark)

V

l

B

y x

A

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7.

(b) The following set-up was used to study the laws of electrical circuits.

A1, A2, A3 and A4 represent ammeters in the circuit.

The readings were as follows:

A1 A2 A3 A4

1.8 A 1.3 A 0.3 A 0.2 A

(i) Write a relation between the current shown in ammeters A1, A2, A3

and A4.

________________________________________________________ (½ mark)

(ii) If another ammeter is connected at point X, what would it read?

________________________________________________________ (½ mark)

(iii) A voltmeter, V, connected across the rheostat reads 5.4 V. Write Kirchoff’s voltage rule for the loop ABCDEA.

_______________________________________________________________________

(1 mark)

Turn Over 5

8 V

A

B C D

E

v

X A2

A3

A4

A1 2 ΩΩΩΩ

2 ΩΩΩΩ 4 ΩΩΩΩ

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8.

QUESTION 5

In an experiment to test the suitability of SHM as a model for the behaviour of a real oscillator, a long length of strong string is hung from the ceiling and is attached to a heavy mass which nearly touches the floor.

The materials are set up as shown in the diagram.

The ticker-timer tape is analysed and the values of acceleration, a and displacement, x were tabulated.

(i) Why is it important to choose a heavy mass for this pendulum?

_____________________________________________________________________________

(1 mark)

(ii) Describe one way of locating the point from which displacement, x is measured.

_____________________________________________________________________________

(1 mark)

(iii) Sample data for this experiment is given below.

a (ms-2) x (m)

+ 3 − 0.9

+ 1.6 − 0.4

− 1 + 0.3 − 2 + 1.1 − 3 + 0.9

Using the above data, plot a graph of a versus x on the graph paper provided.

© MINISTRY OF EDUCATION, FSFCE 2013: PHYSICS. •

• A.C.

~

low volt power supply

Ticker timer Paper

tape

Large mass

Mass caught

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9.

(2 marks)

(iv) If the graph you have drawn in part (iii) shows a relationship a = − kx where − k is the gradient of the graph and for a simple harmonic motion a = − ω2_{x ,} write T, the period of the motion, in terms of k.

_____________________________________________________________________________

(1 mark)

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10.

QUESTION 6

Shown below is an experimental set-up of Forced Vibrations of a String with measured values.

(i) What is the purpose of the stroboscope?

_____________________________________________________________________________

(1 mark)

(ii) Is there a node at the vibrator? Explain your answer.

_____________________________________________________________________________

(1 mark)

(iii) One of the two sources of errors in this experiment is friction in the pulley. What is the second contributing factor?

_____________________________________________________________________________

(1 mark)

(iv) Calculate the theoretical velocity of the wave.

_____________________________________________________________________________

(2 marks)

5

String fixed to A.C. vibrator Pulley

Mass Stroboscope

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11.

QUESTION 7

(a) In an experiment to observe forced vibrations and resonance, the following results were obtained.

Pendulum

0 1

n

n Amplitude (cm)

1 1.25 5

2 1.11 13

3 1.00 32

4 0.91 11

5 0.83 6

(i) From the results, which pendulum is expected to undergo resonance in this experiment?

_______________________________________________________________________

_______________________________________________________________________ (1 mark)

(ii) What can be concluded from this experiment?

_______________________________________________________________________

(1 mark)

(b) Given below is a diagram of a screen display of an oscilloscope which is placed across the resistance, R.

(i) What is the value of the root mean square (r.m.s.) voltage across the resistance, R? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ (1½ marks) Turn Over 1 ms

100 µs 10 µs 1 µs 10 ms

100 ms OFF

TIME PER cm Timebase

5 2 1 5 10 20

50

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(ii) Find the value of the frequency of the signal generator.

_______________________________________________________________________

(1½ marks)

QUESTION 8

Diagram A shows drops of water falling from a burette to a water surface causing waves to move across the surface.

Diagram B shows a view looking down on the water surface showing the pattern of the surface waves against a background of centimetre squares.

(i) Determine the number of drops, “f ”, falling on the water surface per second, if the speed of the water waves is 0.4 m/s.

_____________________________________________________________________________

(1 mark)

5

•

cm

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13.

The burette is now moved slowly at a steady speed. Diagram C below shows the resulting wave pattern.

(ii) State the direction the burette is moved and determine the wavelength of the moving wave.

_____________________________________________________________________________

(1 mark)

(iii) Determine the speed of the burette.

_____________________________________________________________________________

(1 mark)

(iv) An observer is viewing the waves directly to the left of the centre of the wave pattern. She counts the number of crest per second, ‘f ’ passing her. Calculate the value of ‘f ’.

_____________________________________________________________________________

(2 marks)

THE END

C

•

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INDEX NUMBER

PHYSICS PAPER 2

FOR MARKER’S USE

Ques. No.

Marks Gained

Check Mark

1

2

3

4

5

6

7

8