Sound Class 8 MCQs Questions with Answers
I. Choose the correct option.
Question 1.
The voice box is also called as
(a) stomach
(b) heart
(c) larynx
(d) mouth
Answer
Answer: (c) larynx
Question 2.
Sound is a kind of
(a) work
(b) energy
(c) force
(d) pressure
Answer
Answer: (b) energy
Question 3.
The hearing range of human ear is
(a) 20 Hz to 20,000 Hz
(b) less than 20 Hz
(c) more than 20,000 Hz
(d) 20 Hz to 25,000 Hz
Answer
Answer: (a) 20 Hz to 20,000 Hz
Question 4.
Pitch of sound is determined by its
(a) frequency
(b) speed
(c) amplitude
(d) loudness
Answer
Answer: (a) frequency
Question 5.
The frequency of subsonic sound is
(a) more than 20 Hz
(b) 100 Hz
(c) less than 20 Hz
(d) more than 20,000 Hz
Answer
Answer: (c) less than 20 Hz
Question 6.
Cochlea is a part of
(a) hearing organ
(b) sound producing organ
(c) muscular organ
(d) air pollution
Answer
Answer: (a) hearing organ
Question 7.
1 hertz is equal to
(a) 1 vibration per minute
(b) 10 vibrations per minute
(c) 60 vibrations per minute
(d) 600 vibrations per minute
Answer
Answer: (c) 60 vibrations per minute
Question 8.
Sound cannot travel through
(a) air
(b) water
(c) iron
(d) vacuum
Answer
Answer: (d) vacuum
Question 9.
The sound in the audible range is called
(a) ultrasonic sound
(b) sonic sound
(c) subsonic sound
(d) light sound
Answer
Answer: (b) sonic sound
Question 10.
Speed is
(a)
(b)
(c) Distance travelled × Time
(d) Time + Distance travelled
Answer
Answer: (a)
Question 11.
A pendulum oscillates 20 times in 4 seconds. Find its time period.
(a) 0.05 sec.
(b) 0.001 sec.
(c) 0.2 sec.
(d) 0.1 sec.
Answer
Answer: (c) 0.2 sec.
Question 12.
Loudness of sound is determined by
(a) pitch
(b) frequency
(c) amplitude
(d) time period
Answer
Answer: (c) amplitude
Question 13.
The number of vibrations made by a vibrating body in one second is
(a) frequency
(b) noise
(c) loudness
(d) pitch
Answer
Answer: (a) frequency
Question 14.
The maximum displacement of a body from its mean position is called
(a) amplitude
(b) oscillation
(c) periodic motion
(d) frequency
Answer
Answer: (a) amplitude
Question 15.
The velocity of sound at 20°C is approximately
(a) 3400 m/sec.
(b) 340 m/sec.
(c) 430 m/sec.
(d) 304 m/sec.
Answer
Answer: (b) 340 m/sec.
II. Fill in the Blanks
Question 1.
In human beings sound is produced by ……………..
Answer
Answer: larynx
Question 2.
Sound of frequency lower than 20 Hz is called the ……………..
Answer
Answer: infrasonic
Question 3.
The …………….. nerve is also present in the inner ear.
Answer
Answer: auditory
Question 4.
Sounds which are unpleasant to the ear is called ……………..
Answer
Answer: noise
Question 5.
Too much noise in our surroundings that causes discomfort is called ……………..
Answer
Answer: noise pollution
Question 6.
The speed of sound is maximum in ……………..
Answer
Answer: solids
Question 7.
Sounds of frequencies higher than 20,000 Hz are called the …………….. sound.
Answer
Answer: ultrasonic
Question 8.
…………….. is the time taken by a vibrating body for one complete vibration.
Answer
Answer: Time period
Question 9.
Above …………….. the noise becomes physically painful.
Answer
Answer: 80 dB
Question 10.
Plantation on the roadside can reduce ……………..
Answer
Answer: noise pollution
Question 11.
The hearing range of human ears is ……………..
Answer
Answer: 20 Hz to 20,000 Hz
Question 12.
The loudness of normal breathing of human is ……………..
Answer
Answer: 10 dB
Question 13.
Vibration is a repeated …………….. and …………….. motion.
Answer
Answer: fro
Question 14.
The loudness of sound is determined by the …………….. of vibration.
Answer
Answer: amplitude
Question 15.
The human voice box is called ……………..
Answer
Answer: larynx
III. True or False
Question 1.
All human beings can hear sounds of frequencies upto 60,000 Hz.
Answer
Answer: False
Question 2.
The sound in a sitar is produced by plucking its strings.
Answer
Answer: True
Question 3.
Sound cannot travel through vacuum.
Answer
Answer: True
Question 4.
Sound does not need a medium for its propagation.
Answer
Answer: False
Question 5.
The loudness is expressed in a unit called decibel.
Answer
Answer: True
Question 6.
Loud sounds have high frequencies.
Answer
Answer: False
Question 7.
Sound travel faster in air, slower in iron.
Answer
Answer: False
Question 8.
Light travels much faster than sound.
Answer
Answer: True
Question 9.
Man cannot hear sound of bats.
Answer
Answer: True
Question 10.
The time taken to complete one oscillation is called frequency.
Answer
Answer: False
Question 11.
Shriller sound has more frequency.
Answer
Answer: True
Question 12.
Tabla is a musical instrument.
Answer
Question 13.
The sound could not travel in solid.
Answer
Answer: False
Question 14.
The pitch of a sound depends in the frequency of the waves.
Answer
Answer: True
IV. Match the following
| Column I | Column II |
| 1. Audible frequencies | (a) 10 dB |
| 2. Length of vocal cords in man | (b) 30 dB |
| 3. Ultrasound | (c) 20 mm long |
| 4. Normal breathing | (d) 20 to 20,000 Hz |
| 5. Soft whisper (At 5 m) | (e) Hertz |
| 6. Frequency | (f) Percussion instrument |
| 7. Unpleasant sound | (g) Music |
| 8. Pitch | (h) Produced by bats |
| 9. Tabla | (i) Noise |
| 10. Pleasant sound | (j) Higher frequency |
Answer
Answer:
| Column I | Column II |
| 1. Audible frequencies | (d) 20 to 20,000 Hz |
| 2. Length of vocal cords in man | (c) 20 mm long |
| 3. Ultrasound | (h) Produced by bats |
| 4. Normal breathing | (a) 10 dB |
| 5. Soft whisper (At 5 m) | (b) 30 dB |
| 6. Frequency | (e) Hertz |
| 7. Unpleasant sound | (i) Noise |
| 8. Pitch | (j) Higher frequency |
| 9. Tabla | (f) Percussion instrument |
| 10. Pleasant sound | (g) Music |
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