MCQ Characteristics of Sound Waves Chapter 12 Class 9 Science

MCQ’s For All Chapters – Science Class 9th

1. There will be total 24 MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying

1. Which of the following correctly relates the wavelength λ, frequency f and velocity v of sound?

v = λ² f

f = λ - v

f = λ v²

v = f λ

Question 1 of 24

2. The wavelength of the sound produced by a tuning fork of frequency 450 Hz which is set to vibrate in air (take velocity of sound in air as 320 m/s) is

144 cm

0.07 m

7.1 cm

0.711 m

Question 2 of 24

3. A siren has 16 holes and is making 960 revolutions per minute. The frequency of the sound produced by the siren is:

256 Hz

512 Hz

960 Hz

128 Hz

Question 3 of 24

4. SI unit of frequency is

metre

seconds

hertz

metre per second

Question 4 of 24

5. Arrange in increasing order - Speed of sound in steel, in distilled water, in sea water and in oxygen.

Oxygen < distilled water < sea water < steel.

Steel > distilled water > sea water > oxygen.

Oxygen < distilled water = sea water < steel.

Steel < distilled water = sea water < oxygen.

Question 5 of 24

6. A top makes 16 rotations about its own axis within 0.4 seconds, its frequency is:

40 Hz

4 Hz

0.4 Hz

400 Hz

Question 6 of 24

7. On which quantity does the pitch of the sound depend?

Frequency

Amplitude

Speed

wavelength

Question 7 of 24

8. What is the difference between a low pitched and high pitched sound?

high pitched sound has a higher frequency than low pitched sound

high pitched sound has a larger amplitude

low pitched sound has a larger amplitude

both sounds have same frequency but different amplitudes

Question 8 of 24

9. A compression is a region of

high frequency

high pressure

low frequency

low pressure

Question 9 of 24

10. Sound from a flute and sound from a harmonica played by passing air through musical instrument, at same time and same distance from ear and traveling through same medium air, they differ in sounds due to difference in

Wavelength

Speed of sound in air

Pitch

Amplitude

Question 10 of 24

11. A stationary rail engine produces whistle with a frequency 2600 Hz. A person standing at a distance of 550 m from engine will listen ___________ no. of waves within one minute.

156 x 10³

26 x 10⁴

26 x 10⁵

156 x 10⁵

Question 11 of 24

12. If we increase the temperature of air from 0°C to 22°C, then the speed of sound would

Increases till 11ºC and then decreases.

Remain same

Increase

Decrease

Question 12 of 24

13. Compressions are the regions where

Density as well as pressure is low

Density is high pressure is low

Density is low pressure is high

Density as well as pressure is high

Question 13 of 24

14. By counting the number of vibrations of a tuning fork per second, ___________ can be found.

density of the medium

frequency of the wave

amplitude

timbre of sound

Question 14 of 24

15. A bell vibrates 600 times within 3/2 seconds, its frequency and time period will be:

900 Hz, 0.0011 s

400 Hz; 0.25s

400 Hz; 0.0025s

900 Hz; 1.1 s

Question 15 of 24

16. A swing has a time period of 1.4 seconds. The no. of oscillations made by it within 1 minute 24 seconds will be:

60

20

40

80

Question 16 of 24

17. Choose one of the following, on which the frequency of a vibrating body does not depend.

its elastic constants

mode of vibration

medium

dimensions

Question 17 of 24

18. A baby cries with a frequency 712 Hz, if the speed of sound in air is 356m/s, the wavelength of sound is:

0.05m

5 m

0.005 m

0.5 m

Question 18 of 24

19. A progressive transverse wave has a speed of 5040 m/s, its frequency is 315 Hz, then the distance between a crest and an immediate trough is:

800 m

0.8 m

80 m

8 m

Question 19 of 24

20. Sound of single frequency is called

Noise

Tone

Note

Music

Question 20 of 24

21. Assertion : The speed of sound in solids is maximum though their density is large.
Reason : The coefficient of elasticity of solid is large.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true and R is not the correct explanation of A

(c) A is true but R is false

(d) A is False but R is true

Question 21 of 24

22. Assertion : Compression and rarefaction involve changes in density and pressure.
Reason : When particles are compressed, density of medium increases and when they are rarefied, density of medium decreases.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true and R is not the correct explanation of A

(c) A is true but R is false

(d) A is False but R is true

Question 22 of 24

23. Assertion : The velocity of sound in hydrogen gas is less than the velocity of sound in oxygen gas.
Reason : The density of oxygen is more than the density of hydrogen.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true and R is not the correct explanation of A

(c) A is true but R is false

(d) A is False but R is true

Question 23 of 24

24. Assertion : The velocity of sound increases with increase in humidity.
Reason : Velocity of sound does not depend upon the medium.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true and R is not the correct explanation of A

(c) A is true but R is false

(d) A is False but R is true

Question 24 of 24

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