Important MCQ on Sound Waves for competitive exams like SSC JKSSB
JKPSC RRB SSC-CGL
1. What type of waves are Sound Waves?
A.
Latitudinal waves
B. Longitudinal waves
C. Latitudinal
mechanical waves
D. Longitudinal waves
Ans. D
Sound Waves are longitudinal mechanical waves.
2. Which of the following is/ are not applications of Ultrasonic
Waves?
(a) For measuring the depth of Sea.
(b) In sterilizing of
a liquid.
(c) In Ultrasonography
(d) In sterilizing a
needle.
Options are:
A. Both (a) and (b)
Only (b)
B. Only (d)
C. Both (c) and (d)
D. Only (b)
Ans. B
Applications of Ultrasonic Waves are: sending signals, for
measuring the depth of sea, for cleaning cloths, aeroplanes, machinery
parts of clocks, for removing lamp-shoot from the chimney of
factories, in sterilizing of liquid and in Ultrasonography.
3. What is the speed of sound in air?
A. 330 m/s
B. 332 m/s
C. 334 m/s
D. 336 m/s
Ans. B
The speed of Sound in Air (00C) is 332 m/s and in
Air (200C) is 343 m/s.
4. What will be the effect of temperature on speed of
sound?
A. The speed of sound decreases with the increases of
temperature of the medium.
B. The speed of sound decreases with
the decrease of temperature of the medium.
C. The speed of sound
increases with the decrease of temperature of the medium.
D. The
speed of sound increases with the increase of temperature of the
medium.
Ans. D
5. Name the characteristic of the sound which distinguishes a sharp
sound from a grave or dull sound?
A. Intensity
B. Echo
C. Pitch
D. Resonance
Ans. C
Pitch is that characteristic of sound which distinguishes a
sharp or shrill sound from a grave or dull sound. It depends upon
frequency. Higher the frequency higher will be the pitch and shriller
will be the sound and vice versa.
6. Due to which phenomena sound is heard at longer distances
in nights than in day?
A. Reflection
B. Refraction
C. Interference of
sound
D. Diffraction of sound
Ans. B
Due to refraction, sound is heard at longer distances in nights
than in day.
7. When a motor boat in a sea travels faster than sound, then waves
just like shock-waves are produced on the surface of water. These
waves are called ..............
A. Shock waves
B. Doppler’s waves
C. Refracted
waves
D. Bow waves
Ans. D
When a motor
boat in a sea travels faster than sound, then waves just like
shock-waves are produced on the surface of water. These waves are
called bow waves.
8. What is Intensity of Sound?
A. It is inversely proportional to the square of the distance
of point from the source.
B. It is directly proportional to the
square of amplitude of vibration, square of frequency and density of
the medium.
C. Both A and B
D. Neither A nor B
Ans. C
Intensity of any sound at any point in space is the amount of
energy passing normally per unit area held around that point per unit
time. S.I unit of intensity is watt/m2.
9. What is the unit of loudness?
A. Bel
B. Phon
C. Decibel
D. All of the above
Ans D
The sensation of a sound perceived in a ear is measured by
another term called loudness which depends on intensity of sound and
sensitiveness of the ear. Unit of loudness is bel. A practical unit of
loudness is decibel (dB) which is 1/10th of bel. Another unit of
loudness is phon.
10. Which of the following statement is or are correct about
longitudinal mechanical waves?
A. The longitudinal mechanical waves which lie in the frequency
range 20 Hz to 20000 Hz are called audible or sound waves.
B. The
longitudinal mechanical waves having frequencies less than 20 Hz are
called infrasonic.
C. The longitudinal mechanical waves having
frequencies greater than 20,000 Hz are called ultrasonic waves.
D.
All of the above are correct
Ans. D
Sound
or Audible waves are sensitive to human ear and are generated by the
vibrating bodies like tuning fork, vocal cords etc. Infrasonic waves
are produced by sources of bigger size such as earth quakes, volcanic
eruptions, ocean waves etc. Human ear cannot detect Ultrasonic waves.
But dog, cat, bat etc can detect these waves. Bat not only detect but
also produce ultrasonic waves.