NCERT MCQ CLASS-9 CHAPTER-12 | SOUND | EDUGROWN

NCERT MCQ ON SOUND

Question 1.
For hearing a distinct sound, the time interval between the original sound and the reflected one must be at least:
(a) 1 s
(b) 0.1 s
(c) 2 s
(d) 0.2 s

Answer: (b) 0.1 s

Question 2.
The persistence of sound in an auditorium is the result of repeated reflections of sound and is called:
(a) reverberation
(b) audible
(c) distinct sound
(d) reflection

Answer: (a) reverberation

Question 3.
The speed v, frequency υ, and wavelength λ, of sound are related by the equation:
(a) v = λυ
(b) υ = λv
(c) λ = υv
(d) v = λυ

Answer: (a) v = λυ

Question 4.
The speed of sound is maximum in:
(a) solids
(b) liquids
(c) gases
(d) All of these

Answer: (a) solids

Question 5.
Our ears are sensitive to sound frequencies between:
(a) 20 Hz to 20 kHz
(b) 2 Hz to 20 Hz
(c) 20 kHz to 200 kHz
(d) 2000 kHz to 20000 kHz

Answer: (a) 20 Hz to 20 kHz

Question 6.
Which of the following waves are produced by bats?
(a) Infrasonic waves
(b) Ultrasonic waves
(c) Audible waves
(d) All of these

Answer: (b) Ultrasonic waves

Question 7.
Maximum tolerable sound is:
(a) 0 dB
(b) 10 dB
(c) 60 dB
(d) 120 dB

Answer: (d) 120 dB

Question 8.
Sound waves are:
(a) magnetic waves
(b) electric waves
(c) electromagnetic waves
(d) mechanical waves

Answer: (d) mechanical waves

Question 9.
In SONAR, we use:
(a) ultrasonic waves
(b) infrasonic waves
(c) radio waves
(d) audible sound waves

Answer: (a) ultrasonic waves

Question 10.
Sound travels in the air if:
(a) particles of medium travel from one place to another
(b) there is no mixture in the atmosphere
(c) disturbance moves
(d) both particles as well as disturbance travel from one place to another

Answer: (c) disturbance moves

Question 11.
When we change feeble sound to loud sound we increase its:
(a) frequency
(b) amplitude
(c) velocity
(d) wavelength

Answer: (b) amplitude

Question 12.
In the curve half the wavelength is:

(a) AB
(b) BD
(c) DE
(d) AE

Answer: (b) BD

Question 13.
An earthquake produces which kind of sound before the mainshock wave begins:
(a) ultrasound
(b) infrasound
(c) audible sound
(d) None of the above

Answer: (b) infrasound

Question 14.
Infrasound can be heard by:
(a) dog
(b) bat
(c) rhinoceros
(d) human beings

Answer: (c) rhinoceros

Question 15.
Sound travels as a _______ wave through a material medium.

(a) transverse
(b) longitudinal
(c) zigzag
(d) straight line

Answer: (b) longitudinal

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