Physics - Study Mode
[#286] Sound becomes hazardous noise pollution at decibels?
Correct Answer
(B) Above 80 db
Explanation
Solution: Sound levels are measured in decibels(dB), sound level of 80 or more dB can aptly be called noise which can cause serious hearing loss, tensions, high blood pressure, it can induce several disorders prematurely existing, such as hypertension, an increase in blood cholesterol level and is detrimental to health in other aspects when observed for more than maximum tolerable limit of 50 dB. Hence, the correct answer is 'Above 80 dB'.
[#287] What is the SI unit of intensity of sound?
Correct Answer
(A) Decibel
Explanation
Solution: Decibel is the SI unit of intensity of sound.
[#288] Sound cannot pass through
Correct Answer
(D) Vacuum
Explanation
Solution: Sound cannot travel through a perfect vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibration to work in.
[#289] Sound waves cannot travel in
Correct Answer
(A) Vacuum
Explanation
Solution: Sound cannot travel through a perfect vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibration to work in.
[#290] The quality or tone of a musical sound produced by a stringed instrument depends on
Correct Answer
(D) Wave form of the sound
Explanation
Solution: The timbre or quality of a sound depends on its wave form, which varies with the number of overtones, or harmonics, that are present, their frequencies, and their relative intensities. In simple terms, timbre is what makes a particular musical sound have a different sound from another, even when they have the same pitch and loudness.