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Vidaara.orgClass 7 · Mathematics
CodeVID-M7-WS
Sound — Practice Worksheet
Chapter: Sound
Topic: Sound
Maximum Marks: 25
Time: 30 minutes
Name: ____________________ Roll No.: __________ Date: ____________

General Instructions

  • All questions are compulsory.
  • Choose the correct option (A, B, C or D) for each question.
  • The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each) 25 × 1 = 25 marks
1.
Sound is always produced by an object that is:
  • A.Heated
  • B.Vibrating
  • C.Stretched
  • D.Charged
2.
Sound waves are classified as:
  • A.Transverse waves
  • B.Longitudinal waves
  • C.Light waves
  • D.Surface waves
3.
Sound cannot travel through:
  • A.A solid
  • B.A liquid
  • C.A gas
  • D.A vacuum
4.
A region in a sound wave where the medium's particles are pushed close together is a:
  • A.Rarefaction
  • B.Compression
  • C.Reflection
  • D.Refraction
5.
The bell-jar experiment, in which a bell becomes silent as air is removed, proves that sound:
  • A.Travels faster in air
  • B.Needs a material medium
  • C.Is a transverse wave
  • D.Cannot be reflected
6.
The loudness of a sound depends mainly on the wave's:
  • A.Frequency
  • B.Amplitude
  • C.Quality
  • D.Speed
7.
The pitch of a sound is determined by its:
  • A.Amplitude
  • B.Frequency
  • C.Loudness
  • D.Timbre
8.
The number of vibrations made in one second is the frequency, measured in:
  • A.Decibels
  • B.Joules
  • C.Hertz
  • D.Metres
9.
The characteristic that lets us tell a flute from a guitar playing the same note is:
  • A.Loudness
  • B.Pitch
  • C.Quality (timbre)
  • D.Amplitude
10.
If a vibrating body has a frequency of 25 Hz, its time period is:
  • A.25 s
  • B.0.04 s
  • C.2.5 s
  • D.50 s
11.
Sound travels fastest through which type of material?
  • A.Gases
  • B.Liquids
  • C.Solids
  • D.Vacuum
12.
The approximate audible range of frequencies for humans is:
  • A.0 – 20 Hz
  • B.20 – 20,000 Hz
  • C.20,000 – 40,000 Hz
  • D.1 – 10 Hz
13.
Sound of frequency above 20,000 Hz is called:
  • A.Infrasound
  • B.Audible sound
  • C.Ultrasound
  • D.Echo
14.
We see lightning before hearing thunder because:
  • A.Sound is faster than light
  • B.Light is faster than sound
  • C.Thunder comes first
  • D.Light needs no medium only
15.
A ship measures the depth of the sea using ultrasound through a technique called:
  • A.Radar
  • B.SONAR
  • C.Ultrasonography
  • D.Echo-writing
16.
A distinct repetition of a sound heard after reflection from a far surface is called:
  • A.Reverberation
  • B.An echo
  • C.A vibration
  • D.A compression
17.
For an echo to be heard separately, the reflected sound must return after at least:
  • A.0.01 s
  • B.0.1 s
  • C.1 s
  • D.10 s
18.
Sound is reflected best by surfaces that are:
  • A.Soft and rough
  • B.Hard and smooth
  • C.Porous and woolly
  • D.Curtained
19.
The lingering of sound due to repeated overlapping reflections in a hall is called:
  • A.Echo
  • B.Reverberation
  • C.Refraction
  • D.Resonance
20.
Reverberation in a cinema hall is reduced by covering the walls with:
  • A.Polished metal
  • B.Glass sheets
  • C.Sound-absorbing materials
  • D.Smooth tiles
21.
A pleasant sound produced by regular vibrations is called a:
  • A.Noise
  • B.Musical sound
  • C.Echo
  • D.Reverberation
22.
The presence of excessive or unwanted sound in the environment is called:
  • A.Air pollution
  • B.Noise pollution
  • C.Water pollution
  • D.Light pollution
23.
Which of the following is a major source of noise pollution?
  • A.Whispering
  • B.A flowing stream
  • C.Vehicle horns
  • D.Rustling leaves
24.
Continuous exposure to loud noise can cause:
  • A.Better hearing
  • B.Hearing loss and stress
  • C.Improved sleep
  • D.Lower blood pressure
25.
Planting trees along roadsides helps control noise pollution because trees:
  • A.Reflect all sound
  • B.Absorb and scatter sound
  • C.Produce louder sounds
  • D.Increase echoes

Answer Key

Section A — Multiple Choice (1 mark each)
  1. (B) Vibrating
  2. (B) Longitudinal waves
  3. (D) A vacuum
  4. (B) Compression
  5. (B) Needs a material medium
  6. (B) Amplitude
  7. (B) Frequency
  8. (C) Hertz
  9. (C) Quality (timbre)
  10. (B) 0.04 s
  11. (C) Solids
  12. (B) 20 – 20,000 Hz
  13. (C) Ultrasound
  14. (B) Light is faster than sound
  15. (B) SONAR
  16. (B) An echo
  17. (B) 0.1 s
  18. (B) Hard and smooth
  19. (B) Reverberation
  20. (C) Sound-absorbing materials
  21. (B) Musical sound
  22. (B) Noise pollution
  23. (C) Vehicle horns
  24. (B) Hearing loss and stress
  25. (B) Absorb and scatter sound
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