Physics work sheet

2nd term portion

Paper -2
TOPIC: Sound

1. The boy shown in Fig. 1.1 has just thrown a number of stones into a
pond, one after the other. Fig. 1.1 shows the crests of the waves a
short time after the stones landed in the water.

Fig 1.3
Fig 1.1 (i) From Fig. 5.3, what can be deduced about the speed of the wave?
(a) On Fig. 1.1, mark with a cross the point where the stones hit the ...................................................................................................................
water. [1] ...................................................................................................................
(b) Fig. 1.2 shows a section through the surface of the water before ...............................................................................................................[2]
the stones land.
(ii) On Fig. 5.3, draw the wave front 8 s after the stone landed. [2]
[Total: 7]

Fig 1.2
On Fig. 1.2, sketch what the section of the surface might look like at
the instant shown in Fig. 1.1. [2] 2. (a) State what is meant by the echo of a sound.
............................................................................................................
(c) Later, the boy throws a single stone into the water. Fig. 1.3 shows, ............................................................................................................
from above, the position of the wave front at 2 s, 4 s and 6 s after the ........................................................................................................[2]
stone landed.
(b) Describe how the echo of a sound may be demonstrated.
Include a diagram that shows approximate sizes and distances.

diagram
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 (a) On Fig. 3.1, measure carefully, in mm, the wavelength of the
wave.

wavelength = ............................................ mm [2]

(b) State what is meant by

description of method
............................................................................................................ (i) the frequency of a wave,
............................................................................................................ ...................................................................................................................
............................................................................................................ ...................................................................................................................
............................................................................................................
............................................................................................................ (ii) the amplitude of a wave.
........................................................................................................[3] ...................................................................................................................
............................................................................................................. [3]
(c) The demonstration in (b) is used to find the speed of sound in
air. (c) A large barrier, of height greater than the height of the wave in
Fig. 3.1, is put in the path of the wave.
(i) Which two measurements should be made?
1. ....................................................................................................... What, if anything, does this do to the wave?
2. ................................................................................................... [2]
Tick any one:
(ii) State how you would calculate the speed of sound from these o It diffracts the wave.
measurements. o It does nothing to the wave.
............................................................................................................ o It reflects the wave.
............................................................................................................ o It refracts the wave. [1] [Total: 6]
............................................................................................................
........................................................................................[2] [Total: 9] 4. An explosion at X in a quarry is heard by a boy at Y and a girl at
Z. Their relative positions are shown in Fig. 4.1.
3. Fig. 3.1 shows a wave on a water surface, at a particular instant.

Fig 3.1

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 (ii) How does the sound heard by the boy compare with the sound
heard by the girl?

Tick one box.

o The sound heard by the boy is quieter.

o The sounds are equally loud.
o The sound heard by the boy is louder. [1] [Total: 7]

5. Fig. 5.2 shows a wave travelling, in the direction of the arrow,

along a rope.

Fig. 4.1 (not to scale)

(a) The girl hears the explosion 5.0 s after she sees the explosion
happening.
(i) Explain why there is a delay between seeing and hearing the
explosion. Fig 5.1
................................................................................................................... (i) Explain why the wave shown in Fig. 7.2 is described as a
................................................................................................................... transverse wave.
...............................................................................................................[1] ............................................................................................................
...................................................................................................... [1]
(ii) The girl is standing 1700 m from the explosion site X. (ii) The speed of the wave along the rope is 3.2 m / s. Calculate
Calculate the speed of sound. the frequency of the wave.

frequency = .................................................. [3]

speed of sound = ..................................................[4]
6. (a) Draw a straight line from each wave to the most appropriate
(b) The boy is standing at Y, between the explosion site and the girl. speed on the right

(i) When does he hear the explosion? Tick one box.

o immediately it happens
o before the girl
o at the same time as the girl
o later than the girl [1]

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 time difference = ..................................................[4] [Total: 7]

7. A metal rail is 330 m long. Sound travels at 5000 m / s in the metal.

(a) Calculate the time taken for a sound to travel the length of the rail.

time taken = .............................................. s [3]

(b) Sound in air takes 1.0 s to travel 330 m.

As shown in Fig. 7.1, a man puts his right ear against one end of the rail.
Another man strikes the other end of the rail with a hammer.

(b) Fig. 6.1 shows a railway-line testing-team checking a continuous

rail of length 120 m. The diagram is not to scale. Describe and explain what each man hears.

man with hammer .........................................................................................

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

man with one ear against rail ........................................................................

.......................................................................................................................
.................................................................................................. [3] [Total: 6]
One tester strikes one end of the rail with a hammer. The other
tester hears the sound transmitted through the air and transmitted
through the rail. He hears the two sounds at different times.

The speed of sound in steel is 5000 m / s.

Calculate the time difference, using your value from (a) for the speed
of sound in air.