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48 M

On Fig. 1.1, draw a normal at P and mark the angle of incidence with the letter

Fig. 1.1

Optical fibres are used to transmit telephone signals. Fig. 1.1 shows a ray of light that strikes the 1

Test (Unit 12-16)

Adabistan-e-Soophia

2h30m 80

/GIII :........................................................ Code: 5054 Class: GBIII

:................................................................................................................

heory Section:T [Total arks]

Time Allowed: Maximum Marks:

Date

Name Paper: Physics

1

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inside surface of an optical fibre at P.

P

(a) State one advantage of using optical fibres to transmit telephone signals.

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

...............................................................................................................................................[1]

(b) (i) i. [1]

(ii) State and explain what happens to the ray at P. Use the term critical angle in your answer.

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

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

.......................................................................................................................................[2]

(c) The optical fibre is made of glass of refractive index 1.5. At the start of the optical fibre, the ray enters the glass from air. The angle of incidence in the air is 60°.

Calculate the angle of refraction in the glass.

angle = ................................................................[2]

On Fig. 2.1, mark a distance which shows how far a wavefront at X moves in 1.0 s.

On Fig. 2.1, draw an arrow to show the direction of the movement of a water molecule at X.

Fig. 2.1

Fig. 2.1 shows a wave on the surface of water. The wave is travelling to the right.2

2

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X

(not to scale)

(a) Describe what is meant by wave motion.

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

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

...............................................................................................................................................[2]

(b) [1]

(c) The frequency of the water wave is 2.0 Hz and the wavelength is 2.5 cm.

(i) Calculate the speed of the wave.

speed = ...............................................................[2]

(ii) Label this distance D. [1]

On Fig. 3.2, draw a possible echo formed by this burst of ultrasound. [2]

Fig. 3.2

Fig. 3.2 shows the variation with time of air pressure caused by a burst of ultrasound.

Fig. 3.1

3

3

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Fig. 6.1 shows a bat.

Bats emit short bursts of ultrasound. The echoes of the ultrasound help the bat find insects and prevent the bat flying into objects.

(a) State what is meant by an echo.

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

.............................................................................................................................................. [1]

(b)

airpressure

time

(c) State

(i) the approximate range of frequencies of sound audible to humans,

...................................................................................................................................... [1]

(ii) how the frequency of ultrasound differs from frequencies in this audible range.

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...................................................................................................................................... [1]

4

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4 Fig. 4.1 shows a glass lens in air and its two focal points F1 and F2.

lens

threerays

F1 F2

Fig. 4.1

Three rays of light pass through F1 to the lens.

(a) On Fig. 4.1, continue the three rays through the lens and into the air. [2]

(b) State what happens to the speed of light on

(i) entering the glass lens from air,

.......................................................................................................................................[1]

(ii) leaving the lens and returning to the air.

.......................................................................................................................................[1]

(c) Light of wavelength 6.0 × 10–7 m travels in air at a speed of 3.0 × 108 m / s.

(i) Calculate the frequency of this light.

frequency = ....................................................[2]

(ii) State the effect, if any, on the frequency as the light enters the glass from air.

.......................................................................................................................................[1]

Use Fig. 5.2 to determine the frequency of the wave.

On Fig. 5.2, sketch a graph to show how the displacement of B varies with time. [2]

Fig. 5.2

Fig. 5.2 shows how the displacement of A varies with time.

Fig. 5.1

Fig. 5.1 shows circular wavefronts produced at the centre of a circular ripple tank.5

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5

8.0 cm

cork B

cork A

Two corks, A and B, float on the water in the ripple tank. They move up and down on the surface of the water as the wave passes. The wavelength of the wave is 8.0 cm.

+2

00.25 0.50 0.75 1.00 1.25

time / s

displacement/ mm

–2

0

(a) State the amplitude of the vibrations of A as the wave passes.

amplitude = .........................................................[1]

(b) The horizontal distance between A and B is half the wavelength of the wave.

(c) (i)

frequency = .........................................................[2]

(ii) The distance between the centre of the ripple tank and its edge is 40 cm.

Determine the time taken by a wavefront to travel from the centre of the tank to the edge.

time = ..................................................................[2]

Fig. 6.1

Fig. 6.1 represents a microwave travelling in air through points A and B.6

6

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A B distance

(not to scale)

The distance between A and B is 40 cm.

(a) State the speed of microwaves in air.

speed = ...........................................................[1]

(b) Determine the wavelength of the microwave shown in Fig. 4.1.

wavelength = ...........................................................[1]

(c) Describe how microwaves are used in the transmission of television signals by satellite.

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

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

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

...............................................................................................................................................[3]

(d) State two properties common to all electromagnetic waves.

1. ...............................................................................................................................................

2. ...............................................................................................................................................[2]

Fig. 7.2 is complete; no spectrum is produced.

Fig.7.2

Fig. 7.2 shows the same prism with the ray of white light incident at a different angle.

On Fig. 7.1, draw the ray of blue light produced in, and beyond, the prism. [2]

Fig. 7.1 is not complete; it shows only the ray of red light produced from the white light.

Fig.7.1

Fig. 7.1 shows a ray of white light incident on a glass prism.7 7

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glassprism

redlight

redlight

whitelight

(a) (i)

(ii) State two colours of the spectrum found between the red and blue rays.

.............................................................................................................................. [1]

(b)

whitelight

whitelight

Q

(i) Explain why no light emerges from the prism at Q.

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

.............................................................................................................................. [1]

(ii) Explain why no spectrum is produced.

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

.............................................................................................................................. [1]

8

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8 Fig. 8.1 shows a short-sighted eye.

rays of light

eye lensretina

Fig. 8.1

Rays of light from a distant star are parallel as they reach the lens of the eye. Refraction of light as it enters the eye has been ignored in Fig. 8.1.

(a) (i) On Fig. 8.1, continue the rays to show their paths inside the short-sighted eye until they strike the retina. [2]

(ii) Explain how your diagram shows that the image of the star seen by the observer is blurred.

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

.......................................................................................................................................[1]

(b) Fig. 8.2 shows three parallel rays of light.

P

Fig. 8.2

(i) On the line P in Fig. 8.2, draw the shape of a lens that is used to correct short sight. [1]

(ii) On Fig. 8.2, continue the three rays through the lens that you have drawn. [1]

[Total 15 Marks]

Question 4 continues on page 11.

Using Fig. 9.1, measure the angle of incidence

On Fig. 9.1, draw the path of the ray through the block. [1]

On Fig. 9.1, complete the path of the ray after it emerges from the block. [1]

Fig. 9.1 on page 10 shows the semi-circular block on a sheet of white paper.

9

9

ATP Section:

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A semi-circular glass block is used to measure the critical angle for light in glass.

A student shines a narrow ray of light from a ray-box through the semi-circular block and draws two crosses M1 and M2 on the emergent ray.

(a) (i)

(ii)

(iii) i where the light passes from glass to air.

i = .......................................................... [1]

(b) Describe how the student adjusts the apparatus to measure the critical angle for glass. You may use a diagram to help your explanation.

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

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

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

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

.............................................................................................................................................. [2]

10

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M1

ray box

M2

Fig. 4.1

Fig. 9.2

Fig. 9.2 shows the incident ray used by another student. The ray in the block strikes the

11

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(c) glass-air surface at the critical angle.

Explain why it is more difficult to measure the critical angle with this arrangement than with the arrangement in (b).

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

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

.............................................................................................................................................. [1]

Fig. 10.1

in Fig. 10.1.

10

12

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A group of students measures the speed of a wave along a slinky spring.

A teacher and a student hold the ends of a slinky spring stretched along a bench, as shown

bench

spring

five metre rules

The teacher moves one end of the spring to make a wave pulse travel along the spring.Five metre rules are placed end-to-end alongside the spring.Five students with stopwatches stand together near the centre of the spring to measure the time t taken by the wave pulse to travel the distance of 5.0 m.

(a) The five students record the following values for t, measured in seconds.

1.71 1.64 1.78 1.75 1.67

(i) Find the average time tav for the wave to travel 5.0 m along the spring.

tav = ................................................ [1]

(ii) Calculate the average speed vav of the wave pulse along the spring. Give your answer to a suitable number of significant figures.

vav = ................................................ [2]

13

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(b) (i) Explain why, in practice, the position of the students and the metre rules causes a parallax error.

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

............................................................................................................................ [1]

(ii) Explain why this parallax error causes the measured values of t to be too small.

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

............................................................................................................................ [1]

(iii) Explain one other reason why the times recorded by the students are not all exactly the same.

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............................................................................................................................ [1]

(iv) Describe how the students could measure the time t more accurately.

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

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

............................................................................................................................ [2]

(c) One student suggests that the speed of a slower wave pulse can be measured more accurately.

Suggest a method of making a wave pulse travel more slowly along the spring.

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

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

.................................................................................................................................... [1]

3

2

1

[Total 17 Marks]

14

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MCQ Section: Light is incident on a mirror and is reflected as shown.

mirror 80°

What is the angle of incidence and the angle of reflection?

angle of

incidence / °

angle of

reflection / °

A 40 40

B 40 50

C 50 40

D 50 50

Light is incident on one face of a glass block at an angle of incidence of 40°. The glass block is in air.

The refractive index of the glass is 1.46.

What is the angle of refraction inside the glass block?

A 26° B 27° C 58° D 70°

In a short-sighted eye, light from distant objects is not focused on the retina.

Where is this light focused and what type of lens is needed to correct the problem?

where focused lens needed

A behind the retina converging lens

B behind the retina diverging lens

C in front of the retina converging lens

D in front of the retina diverging lens

4

5

6

15

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A man is short-sighted.

Which ray diagram shows what happens in his eye when he looks at a distant object?

A B C D

The diagram shows a ray of light directed at a plane mirror.

40°

mirror

What are the angle of incidence and the angle of reflection?

angle of incidence

angle of reflection

A 40° 40°

B 40° 50°

C 50° 40°

D 50° 50°

Light travels through a glass block as shown.

Which angle is the critical angle for light in the glass?

DC

A

Bair

glass

9

8

7

16

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How do the speed and the wavelength of red light in air compare with the speed and the wavelength of violet light in air?

speed of red light

wavelength of red light

A greater greater

B greater less

C same greater

D same less

A ray of light enters a glass block at an angle of incidence i, producing an angle of refraction r in the glass.

glassblock

r

i

Several different values of i and r are measured, and a graph is drawn of sin i against sin r.

Which graph is correct?

sin i

sin r

Asin i

sin r

Bsin i

sin r

C

1

0.5

00 0.5 1

sin i

sin r

D

1

0.5

00 0.5 1

1

0.5

00 0.5 1

1

0.5

00 0.5 1

A boy stands beside a girl in front of a large plane mirror. They are both the same distance from the mirror, as shown.

Where does the boy see the girl’s image?

A D

B Cmirror

girl boy

12

11

10

17

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The diagram shows the main sections of the electromagnetic spectrum in order of increasing frequency. Some of the sections are labelled.

radiowaves R light

gamma-rays

increasing frequency

The section R has a frequency just below that of light.

Which application uses the section R?

A killing cancerous cells

B satellite television

C sterilisation

D television remote controller

A student uses a spring to demonstrate waves. He moves the spring with his hand.

spring placed on bench

Which diagram demonstrates the type of wave produced by a source of sound?

A B

C D

Waveforms are shown on a cathode-ray oscilloscope for a flute and for a guitar, each playing the same note. The oscilloscope settings are the same for both waveforms.

flute guitar

What is the difference between the two sounds?

A the amplitude

B the frequency

C the quality (timbre)

D the wavelength

15

14

13

18

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A ray of light strikes a plane mirror and is reflected.

x yw z

normal

Which pair of angles must be equal in value?

A w and x B w and y C x and y D x and z

The ray diagram shows two rays from a point on an object placed in front of a diverging (concave) lens.

diverginglens

object

What are the properties of the image produced?

A real and larger than the object

B real and smaller than the object

C virtual and larger than the object

D virtual and smaller than the object

The displacement-distance and displacement-time graphs are for a water wave in a ripple tank.

01 2 3 distance / cm

displacement

00.02 0.04 0.06 time / s

displacement

0 0

What is the speed of the water wave?

A 0.02cm/ s B 0.08cm/ s C 25cm/ s D 50cm/ s

18

17

19

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A student holds a sheet of paper with letters on it facing a plane mirror.

The letters on the paper are shown.

What does the student see in the mirror?

A B C D

A semi-circular block is made from a plastic. A ray of light passes through it at the angles shown.

28°

62°

45°

45°

plastic

air

To two decimal places, what is the refractive index of the plastic?

A 1.25 B 1.41 C 1.51 D 1.61

20

17 A B C D

16 A B C D

15 A B C D

14 A B C D

13 A B C D

12 A B C D

11 A B C D

10 A B C D

Candidate Name:

Example

For question 1,

If you think B is the right answer, fill in

your answer sheet like this:

1 A B C D

Instructions

Shade One letter only for each question

Make sure you put your answer in line

with the correct question number

1 A B C D

2 A B C D

3 A B C D

4 A B C D

5 A B C D

6 A B C D

7 A B C D

8 A B C D

9 A B C D