# Sound MCQ Class 9

## Chapter-12 : Science Class 9 MCQ’s with Answers

Q1.Which of the following is carried by the waves from one place to another

(a) Velocity
(b) Work
(c) Energy
(d) Mass

Ans: Energy

Q2. In a slinky (i.e., a long spring) which of the following types of waves can be generated

(a) Standing only
(b) Longitudinal only
(c) Both A and B
(d) None of these

Ans: Standing only

Q3. In gases a sound wave is

(a) Longitudinal only
(b) Transverse only
(c) both A and B
(d) None of these

Ans: Longitudinal only

Q4. In a transverse wave, the individual particle of the medium move

(a) Perpendicular to the direction of travel
(b) In circle
(c) Parallel in the direction of travel
(d) In ellipses

Ans: Perpendicular to the direction of travel

Q5. A body produces sound only if it is

(c) Vibration

Ans: Vibration

Q6. The SI unit of amplitude of motion is

(a) mm
(b) cm
(c) A
(d) m

Ans: m

Q7. If a wave complete 20 vibration in 2.5s, then its frequency is

(a) 200 Hz
(b) 50 Hz
(c) 20 Hz
(d) 8 Hz

Ans: 8 Hz

Q8. A wave completes 24 cycles in 0.8 s. The frequency of the wave is

(a) 30 Hz
(b) 24 Hz
(c) 12 Hz
(d) 8 Hz

Ans: 30 Hz

Q9. A fan is marked 900 r.p.m.(revolution per minute). What is the frequency of movement of its blades

(a) 900 Hz
(b) 90 Hz
(c) 15 Hz
(d) 10 Hz

Ans: 15 Hz

Q10. The frequency of sound waves can be expressed in

(a) Second
(b) Cycle
(c) Metre per second
(d) Cycle per second

Ans: Cycle per second

Q11. In the above figure which pair of particle are out of phase

(a) 5 and 9
(b) 5 and 7
(c) 4 and 7
(d) 2 and 5

Ans: 5 and 7

Q12. If the distance between a crest and and its consecutive trough is L, then the
wavelength of the wave is given by

(a) L
(b) 2L
(c) 3L
(d) 4L

Ans: 2L

Q13. The reciprocal of frequency is

(a) Wavelength
(b) amplitude
(c) time-period
(d) Wave velocity

Ans: time-period

Q14. Waves formed over water surface are

(a) transverse
(b) longitudinal
(c) both a and b
(d) None of these

Ans: transverse

Q15. The lowest audible frequency for a human being is about

(a) 200 Hz
(b) 20 Hz
(c) 15 Hz
(d) 5 Hz

Ans: 20 Hz

Q16. A tuning fork is vibrating in the air. The number of compressions going past a given point per second

(a) Time-period
(b) Amplitude
(c) Wavelength
(d) Frequency

Ans: Frequency

Q17. The product of time-period and frequency is

(a) Infinitive
(b) Zero
(c) Unity
(d) None of these

Ans: None of these

Q18. When we pluck the wire of a sitar, the waves produced in its wire are :

(a) longitudinal
(b) transverse
(c) both a and b
(d) None of these

Ans: Transverse

Q19. A boat is set into vertical Vibration by waves of speed 5 ms-1 whose crests are
5m apart. The Time period of vertical vibration of the boat is

(a) 4 s
(b) 2 s
(c) 1 s
(d) 0.5 s

Ans: 1 s

Q20. What is the natural of the ocean wave in deep, water

(a) Transverse
(b) Longitudinal
(c) Both a and b
(d) none of these

Ans: Transverse

Q21. Hz is the unit of

(a) Frequency
(b) period
(c) Amplitude
(d) None of these

Ans: Frequency