Physics Practice: Sound (Mock Test 1 - Basic)
1. The phenomenon of hearing the same sound again after reflection from a distant obstacle is called:
2. To hear a distinct echo in air, the minimum distance between the source of sound and the obstacle must be approximately:
3. When a body vibrates with its own natural frequency without any external influence, the vibrations are called:
4. The special case of forced vibrations where the frequency of the external force matches the natural frequency of the body is:
5. Which characteristic of sound depends on its frequency?
6. The unit of loudness is:
7. Ultrasonic sounds have a frequency:
8. The characteristic of sound which distinguishes between two sounds of same pitch and loudness is:
9. Vibrations whose amplitude decreases with time due to friction or air resistance are:
10. The speed of sound in air is approximately:
11. A person hears an echo after $2 \text{ s}$ from a cliff. If the speed of sound is $340 \text{ m/s}$, the distance of the cliff is:
12. Loudness is proportional to the ________ of the amplitude of vibration.
13. SONAR stands for:
14. Natural frequency of a string depends on its length $l$, tension $T$, and mass per unit length $m$ as:
15. In a resonant vibration, the amplitude is ________.
16. Bats use ________ to detect obstacles in their path.
17. A high pitch sound is called a ________ sound.
18. Subjective nature of sound means it depends on:
19. If the tension of a string is increased 4 times, its frequency will become:
20. The persistency of hearing for human ear is:
