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Topics / Sci & Tech

Physics Sound

Asked 3 times in UPSC Prelims · first asked 1995 · last asked 2003

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All 3 questions

Newest first — expand for options, answers, and explanations

Which one of the following statements is not correct?

2003Sci & Tech
AThe velocity of sound in air increases with the increase of temperature
BThe velocity of sound in air is independent of pressure
CThe velocity of sound in air decreases as the humidity increases
DThe velocity of sound in air is not affected by the change in amplitude and frequency

Explanation

In air, the speed of sound rises as temperature increases and is not influenced by changes in pressure. Therefore, options 1, 2, and 4 are accurate. Option 3 is incorrect because the speed of sound in air decreases as humidity rises.

A noise level of 100 decibel would correspond to:

2000Sci & Tech
AJust audible sound
BOrdinary conversation
CSound from a noisy street
DNoise from a machine shop

Explanation

In the field of science and engineering, the decibel is a common unit used to measure sound pressure levels. A noise level of 100 decibels would be equivalent to the noise typically heard in a machine shop.

When the same note is played on a sitar and a flute, the sound produced can be distinguished from each other because of the difference in:

1995Sci & Tech
Apitch, loudness and quality
Bpitch and loudness
Cquality only
Dloudness only

Explanation

In the world of physics, sounds are identified by their pitch, loudness, and quality. The unique quality or timbre of a sound enables our ears to differentiate between sounds that have the same pitch and loudness.