Physics - Study Mode
[#811] When two similar sources vibrate with slightly different frequencies, a regular rise and fall occurs in the loudness of tone. This phenomenon is known as
Correct Answer
(B) Beats
Explanation
Solution: When two similar sources vibrate with slightly different frequencies, a regular rise and fall occurs in the loudness of tone. This phenomenon is known as beats.
[#812] Propagation of sound can be visualised as propagation of ________ variations in the medium
Correct Answer
(C) Density
Explanation
Solution: Pressure is related to the number of particles of the medium in a given volume. More density of the particles in the medium gives more pressure and vice-versa. Thus, propagation of sound may be visualised as propagation of pressure variations or density variations in the medium.
[#813] Permissible noise level at Residential area during night time is :
Correct Answer
(A) 45 dB (A)
Explanation
Solution: In commercial areas, it is 65 dB and 55 dB while in residential areas it is 55 dB and 45 dB during daytime and night respectively.
[#814] Calculate the time period (in seconds) of a sound wave of wavelength 4m traveling with a speed of 500m/s
Correct Answer
(D) 0.008
Explanation
Solution: Frequency = velocity/wavelength
= 500/4
= 125
Time period = 1/Frequency
= 1/125
= 0.008
[#815] Which waves cannot be transmitted through vacuum?
Correct Answer
(C) Sound
Explanation
Solution: Sound waves cannot travel in the vacuum of space because there is no medium to transmit these mechanical waves. Classical waves transfer energy without transporting matter through the medium.