CBSE Class 9 Science Worksheet
Unit 3-Motion, Force and Work - Sound
1.
Fill in the blanks: SI unit of wavelength is _________.
2.
A sound wave has a frequency of 3 kHz and wave length 10 cm. Find its speed of propagation.
3.
Choose the correct option: The distance between a compression and the next rarefaction of a longitudinal wave is ________.
A)
4 ?
B)
0.5?
C)
?
D)
2?
4.
Fill in the blanks: Valley of the wave is called __________.
5.
Choose the correct option: Infrasound can be heard by ________.
A)
bats
B)
dogs
C)
humans
D)
rhinoceros
6.
Which of the following wave don't require any medium to propagate?
A)
sound
B)
light
C)
seismic
D)
none of these
7.
Choose the correct option: Speed of sound is least in _________.
A)
air
B)
solid
C)
metal
D)
liquid
8.
State True/false: Waves produced on water surface are transverse in nature.
A)
true
B)
false
9.
A person is standing between two hills. He shouted loudly and hears first echo after 0.5 sec and second echo after 1 sec. What is distance between two hills?
10.
Choose the correct option: Motion of particles about their mean position in regular intervals of time is called _________.
A)
frequency
B)
wave
C)
resistance
D)
gravity
11.
Why the sound of vibrations of pendulum is not heard?
12.
If the tension in the wire is increased nine times how will the velocity of wave in a string varies?
A)
increases by 9 times
B)
decreases by 9 times
C)
increases by 3 times
D)
decreases by 3 times
13.
In the inner ear what turns the pressure variations into electrical signals?
A)
Cochlea
B)
Pinna
C)
Anvil
D)
Stirrup
14.
Choose the correct option: Speed of the sound depends upon ________.
A)
frequency
B)
wavelength
C)
time period
D)
property of the medium
15.
What is supersonic speed?
16.
Choose the correct option: Sound wave is a _______.
A)
electrical wave
B)
mechanical wave
C)
electromagnetic wave
D)
magnetic wave
17.
Choose the correct option: Compressions are formed where air pressure is ________.
A)
normal
B)
lower
C)
higher
D)
zero
18.
Velocity of sound in air at 0°C is 332m/s. If it increases by 0.6m/s per second for each °C rise in temperature. Find the temperature at which velocity is 350m/s
19.
Choose the correct option: Sound waves with frequencies below the audible range are called ________.
A)
ultrasonic
B)
supersonic
C)
infrasonic
D)
sonic boom
20.
Light travels ________ than sound.
A)
faster
B)
slower
C)
At same speed
CBSE Class 9 Science Worksheet
Unit 3-Motion, Force and Work - Sound
Answers
1.
meter
2.
300m/s
3.
Option B
4.
trough
5.
Option D
6.
Option B
7.
Option A
8.
Option A
9.
255m
10.
Option B
11.
The frequency of vibration of the pendulum is below 20 Hz which does not come in the audible range.
12.
Option C
13.
Option A
14.
Option D
15.
When the speed of an object is greater than the speed of the sound in the air then the speed is called supersonic speed.
16.
Option B
17.
Option C
18.
30°C
19.
Option C
20.
Option A
