Two corks P and Q are floating on the surface of water. When water waves pass by, it is found when P is at its highest point, Q is at its lowest point and vice versa. The wavelength of the water wave might be:

A 24 mm

B 40 mm

C 120 mm

D 180 mm

E 24 mm or 40 mm or 120 mm

P Q

60 mm

1

1 mm

2 mm

2 mm

2 mm

1 mm

2 mm

2 mm

The waveform at a certain instant has a wavelength

A 2 mm

B 3 mm

C 4 mm

D 5 mm

E 7 mm2

A cork is moving up and down due to the passage of a train of waves. The cork takes 0.5 s to rise from its lowest to its highest position. If the velocity of the water waves is 50 mm.s-1, what is the wavelength of the water waves?

A 25 mm

B 50 mm

C 75 mm

D 100 mm

E 125 mm

3

A

B

C

D

E

A waveform is shown at a certain instant. Which two points are rad out of phase?

A (A B) (B C) (C D) (D E)

B (A C) (B D) (C E)

C (A D) (B E)

D (A E)

E no such two points exist

x

y

4

The phase difference between two points is /6 rad. If the distance between these two points is 1 m, what is the wavelength of the wave?

A 1 m

B 3 m

C 6 m

D 12 m

E 36 m

5

A sinusoidal wave is travelling along the positive x-axis. The waveform at an instant is shown. What is the shape of the wave after ¼ period? X

Y

X

Y

X

Y

X

Y

X

Y

X

Y

A

B C

DE

6

A string is set vibrating with a period of 0.25 s. The distance between two points rad out of phase is 0.04 m. The velocity of the wave on the string is:

A 0.32 m.s-1

B 0.01 m.s-1

C 0.016 m.s-1

D 0.02 m.s-1

E 0.04 m.s-1

7

The diagram sows the shape of a transverse wave travelling along an infinite string at a certain instant. At this instant, the points at rest are:

A A I

B A E I

C A C E G F

D C G

E none of the above

X

direction of propagation

E

A

B

C

D

F

G

H

I

8

The diagram shows the shape of a transverse wave travelling along an infinite string at a certain instant. At this instant, which portion of the string is moving upwards?

A C to G

B A to C & G to I

C A to C

D E to I

E whole string

X

direction of propagation

E

A

B

C

D

F

G

H

I

9

The diagram sows the shape of a transverse wave travelling along an infinite string at a certain instant. At this instant, which portion of the string is moving forward?

A C to G

B A to C & G to I

C C to G

D points A C E G I

E no point is moving forward

X

direction of propagation

E

A

B

C

D

F

G

H

I

10

The displacement y of a point P on a plucked string varies with time t. Which graph shows the variation of the velocity of point P with time?

y

t

A BC

D E

v v v

vv

t

t

t

tt

11

The dots (X) represent the position of equally spaced air molecules in the absence of a sound wave and those in (Y) represent their positions when a sound passes through. What is the wavelength of the sound wave?

A dB 2dC 3dD 6dE 12d

d

12

X

Y

A source of sound in air emits sound waves of wavelength 11 m. If the velocity of sound in air is 330 m.s-1, how many vibrations does the source make in 0.1 s?

A 1/3

B 3

C 30

D 33

E 363

13

The vibration of the guitar string gradually dies away. As it does so

A its frequency decreases

B its amplitude decreases

C its phase decreases

D all of the above

E none of the above

14

The stem of a vibrating tuning fork is pressed on a table. Which of the following is correct?

1 The phenomenon is an example of forced vibration 2 The duration of vibration is shorter. 3 The loudness is increased.

A 1 only

B 2 only

C 3 only

D 2 and 3 only

E all of them15

If two identical waves which are in phase are superimposed on each other, which of the following about the resultant wave is true?

A Amplitude (doubled) / Period (doubled) / Wavelength (doubled)

B Amplitude (zero) / Period (unchanged) / Wavelength (unchanged)

C Amplitude (unchanged) / Period (unchanged) / Wavelength (unchanged)

D Amplitude (doubled) / Period (unchanged) / Wavelength (unchanged)

E Amplitude (doubled) / Period (unchanged) / Wavelength (doubled)

16

A standing wave is set up on a string. The diagrams show the shape of the string at five instants of time. In which case is the kinetic energy of the string a maximum?

BA C

D E

17

P is a point on the perpendicular bisector of S1 and S2 where S1 and S2 are two identical sound sources connected to the same signal generator. If a listener starts at P, along which path(s) should he walk so that there is no alternating variation in loudness?

A B only

B A only

C D only

D E and C only

E A and B only

P

E A

BC

D

S1 S2

18

D1 and D2 are two dippers attached to a vibrator and circular waves are generated in a ripple tank. If the wavelength of the waves is 4 mm, constructive interference will occur at

P

D1 D2

QR

A P only B Q only C R only D P & Q only E Q & R only

12 mm

8 mm

14 mm

12 mm12 mm

16 mm

19

S1 and S2 are two identical sound sources connected to the same signal generator. A listener walking along the line MN hears a sound of maximum loudness (intensity) at P and then at Q. The difference |S1 Q – S2 Q| is equal to:

A ¼

B ½

C 1

D 1½

E 2

P

S1

N

QS2

M

20

Water waves on the surface of a pond can be produced by throwing a piece of rock into the water. Which of the following will make the water waves travel faster?

A using a larger rock

B using a smaller rock

C throwing the rock harder into the water

D throwing the rock more gently into the water

E none of the above

21

Consider a transverse stationary (standing) wave in a string. Which of the following is incorrect?

A The nodes are points where the displacement is always zero.

B The antinodes are points where the displacements are maximum

C The nodes are fixed in space.

D The distance between two successive nodes is equal to /2.

E The waveform is stationary, that is, does not change with time.

22

A steel guitar string is stretched between supports that are 60 cm apart and the tension is adjusted so that the speed of transverse waves on the string is 33 m.s-1. The string is then plucked so that it vibrates in its fundamental mode. Estimate the wavelength of the sound in the air produced by this vibration of the string given that the speed of sound in air is about 330 m.s-1.

A 30 cm

B 60 cm

C 120 cm

D 600 cm

E 1200 cm

23

When two notes of nearly equal frequencies f1 and f 2 (f 2 > f 1) are sounded together, beats are heard. Beats are periodic variations in

A pitch, with beat frequency (f 2 - f 1).

B pitch, with frequency (1/2) (f 2 - f 1).

C loudness, with beat frequency (f 2 - f 1).

D intensity, with beat frequency (1/2)(f 2 - f 1).

E intensity, with beat frequency (1/2)(f 2 + f 1).

24

Two signal generators are connected to display the formation of beats on the screen of an oscilloscope. If the time base is set at 0.2 ms.cm-1, the beat frequency is

A 100 Hz

B 200 Hz

C 400 Hz

D 1000 Hz

E 2000 Hz

2.5 cm

25

Imagine that you are standing in the path of an ambulance that is coming straight towards you at a constant speed, while sounding a fixed note on its horn. (Remember to jump out of the way.) As the ambulance approaches, the loudness of the note that you hear

A decreases

B remains constant

C increases

D varies (louder and softer)

E don’t know

26

Imagine that you are standing in the path of an ambulance that is coming straight towards you at a constant speed, while sounding a fixed note on its horn. (Remember to jump out of the way.) As the ambulance approaches, the fundamental frequency of the note that you hear

A decreases

B remains constant

C increases

D varies (higher and lower)

E don’t know

27

Imagine that you are standing in the path of an ambulance that is coming straight towards you at a constant speed, while sounding a fixed note on its horn. Suppose that the fundamental frequency of the note generated by the horn is 920 Hz. We have already seen that the note that you hear gets louder but has constant frequency. What about the value of that frequency compared with that of the horn?

A is less than 920 Hz

B is 920 Hz

C is more than 920 Hz

D could have any value near 920 Hz

E don’t know.28

The ambulance is coming straight towards you at a constant speed, while sounding a fixed note on its horn. The answer to the last question was that the frequency heard by the listener is higher than that of the moving source. What is the reason for that?

A The motion of the horn actually changes the horn's frequency.

B Some of the kinetic energy of the horn is transferred to the air which makes it vibrate faster.

C The horn catches up a bit with wavefronts that it has already emitted, thus compressing the sound's wavelength.

D Don’t know.

E 29

A person stands besides a railway track as a train approaches then passes, sounding a whistle all the time. The true frequency of the whistle is 99 Hz. The highest frequency that the person hears is 110 Hz. What is the frequency of the lowest note the person hears?

A 110 Hz

B 80 Hz

C 90 Hz

D 99 Hz

E 100 Hz

30

How will the frequency f of an electromagnetic wave vary with its wavelength ?

f

f

f

f

f

A B C

D E

31

We cannot see round a corner but we can hear round a corner because of:

A sound wave is longitudinal while light is transverse

B light has a greater velocity than sound

C light has a much shorter wavelength than audible sound

D the ear is not as sensitive as the human ear

E sound can penetrate walls but light cannot

32

Which of the following regions of the electromagnetic spectrum is visible?

A 4 to 7 cm

B 0.04 to 0.07 mm

C 0.004 to 0.007 mm

D 4 to 7 nm

E 400 to 700 nm

33

An electromagnetic wave is found to have a wavelength of 30 mm. To which region of the spectrum does it belong?

A microwaves

B infrared radiation

C visible light

D ultraviolet radiation

E X-rays

34

An electromagnetic wave has its wavelength comparable to that of an infrasonic sound with a frequency of 10 Hz. To which part of the electromagnetic spectrum does it belong? (speed of sound 330 m.s-1)

A microwaves

B infrared radiation

C visible light

D ultraviolet radiation

E radio waves

35

In an X-ray tube, X-rays are produced by

A radioactive decay

B the heating effect of electric current

C nuclear changes

D electronic transitions of outer electrons

E the deceleration of fast moving electrons

36

Dispersion provides evidence that light of different frequencies has

A the same speed in vacuum

B different speeds in vacuum

C the same speed in a medium

D different speeds in a medium

E the same speed in vacuum and in a medium

37

When sunlight passes through a glass prism, it is dispersed into seven colours. This means that:

A sunlight contains the visible part of the em spectrum only

B the visible part of sunlight contains 7 different frequencies

C the frequencies of the visible part of sunlight may be grouped into 7 regions

D sunlight is coloured in passing through the prism

E sunlight contains the 3 primary colours

38

A beam of ultrasound is being emitted from a submarine under water towards the water surface. Which of the following is true?

A The refracted beam leaving the water will bend away from the normal.

B The refracted ray will bend towards the normal.

C Total internal reflection will occur.

D The refracted beam will travel in the same direction as the incident beam.

E The refracted ray will travel along the water surface.

39

The diagram shows a train of water waves in a ripple tank where the water depth changes along XY. Which of the following is true?

X

y1 2 2 > 1

A frequency f1 < f2

B refractive index n1 > n2

C wavelength 1 > 2

D wavelength 1 = 2

E speed v1 < v2

1

2

40

The diagram shows a ray of light passing through three different media. Let the wavelengths in the three media be 1, 2, and 3. Then the ratio 3 / 1 is equal to:

A sin3 / sin1

B sin1 / sin3

C sin3 . sin1/ sin22

D sin2 / sin1

E 1

Medium 2

Medium 1

Medium 3

1

3

2

41

The surface of a material of refractive index 1.8 is coated with a thin film of liquid of refractive index 1.5 and thickness 150 nm. White light falls normally on the thin film. Which of the following wavelengths of light (in air) is not reflected from the film?

A 1500 nm

B 150 nm

C 450 nm

D 600 nm

E 900 nm

42

X and Y are two transparent but partially reflecting glass sheets, separated by a small distance d. When light of wavelength is normally incident on plate X the light emerging from Y is of very low intensity when the distance d is equal to

A n / 2

B (2n+1) / 4

C n

D (n+1/4)

E (2n+1) / 2

X Y

d

43