1. Sound is a form of:
A) Light energy
B) Chemical energy
C) Mechanical energy
D) Electrical energy
Answer: C
2. Sound travels fastest in:
A) Air
B) Water
C) Vacuum
D) Steel
Answer: D
3. The unit of frequency is:
A) Meter
B) Hertz
C) Joule
D) Decibel
Answer: B
4. The normal range of human hearing is:
A) 2 Hz – 200 Hz
B) 20 Hz – 20,000 Hz
C) 200 Hz – 2000 Hz
D) 100 Hz – 10,000 Hz
Answer: B
5. Sound cannot travel through:
A) Solids
B) Liquids
C) Gases
D) Vacuum
Answer: D
6. The loudness of sound depends on its:
A) Frequency
B) Wavelength
C) Amplitude
D) Speed
Answer: C
7. Noise is defined as:
A) Pleasant sound
B) High-frequency sound
C) Unwanted sound
D) Musical sound
Answer: C
8. The unit used to measure sound intensity level is:
A) Watt
B) Pascal
C) Decibel
D) Hertz
Answer: C
9. The speed of sound in air at room temperature is approximately:
A) 150 m/s
B) 340 m/s
C) 1000 m/s
D) 3000 m/s
Answer: B
10. Echo is caused by:
A) Refraction
B) Diffraction
C) Reflection
D) Absorption
Answer: C
11. The minimum distance required to hear an echo clearly is about:
A) 5 m
B) 10 m
C) 17 m
D) 50 m
Answer: C
12. Ultrasonic sounds have frequency:
A) Below 20 Hz
B) Above 20,000 Hz
C) Between 20–200 Hz
D) Equal to 1000 Hz
Answer: B
13. Infrasonic sounds have frequency:
A) Above 20,000 Hz
B) Equal to 20 Hz
C) Below 20 Hz
D) Between 20–2000 Hz
Answer: C
14. Pitch of sound depends on:
A) Amplitude
B) Frequency
C) Speed
D) Medium
Answer: B
15. Which instrument produces sound by vibrating strings?
A) Flute
B) Drum
C) Guitar
D) Trumpet
Answer: C
16. Noise pollution mainly affects:
A) Water quality
B) Soil fertility
C) Hearing ability
D) Plant growth only
Answer: C
17. SONAR works on the principle of:
A) Refraction
B) Absorption
C) Reflection of sound
D) Diffusion
Answer: C
18. The device used to measure sound level is:
A) Thermometer
B) Barometer
C) Audiometer
D) Speedometer
Answer: C
19. Sound waves are:
A) Transverse waves
B) Longitudinal waves
C) Electromagnetic waves
D) Surface waves
Answer: B
20. Increasing amplitude increases:
A) Pitch
B) Frequency
C) Loudness
D) Speed
Answer: C
21. Which of the following is an example of noise?
A) Orchestra music
B) School bell
C) Traffic horn
D) National anthem
Answer: C
22. The time period of a wave is the reciprocal of:
A) Speed
B) Wavelength
C) Frequency
D) Amplitude
Answer: C
23. Which medium carries sound waves in space?
A) Air
B) Water
C) Steel
D) None
Answer: D
24. The quality or timbre of sound depends on:
A) Waveform
B) Speed
C) Medium only
D) Distance
Answer: A
25. Bats use which type of sound for navigation?
A) Infrasonic
B) Audible
C) Ultrasonic
D) Musical
Answer: C
26. Noise level above ______ dB can damage hearing.
A) 20
B) 40
C) 85
D) 10
Answer: C
27. Which factor does NOT affect speed of sound?
A) Temperature
B) Density of medium
C) Humidity
D) Amplitude
Answer: D
28. Reverberation is due to repeated:
A) Refraction
B) Reflection
C) Diffusion
D) Transmission
Answer: B
29. Sound energy is produced by:
A) Rotation
B) Vibration
C) Condensation
D) Evaporation
Answer: B
30. Plantation of trees helps to reduce:
A) Air pressure
B) Water pollution
C) Noise pollution
D) Soil erosion only
Answer: C