No verified paper has been uploaded for AJKPSC-PMS Paper Physics 2001 MCQs yet.
The MCQs below are drawn from the Physics subject category.
Showing 1051–1060
of 15721 MCQs
Page 106 / 1573
1051
A sonometer wire, 65 cm long, is in resonance with a tuning fork of frequency N. If the length of the wire is decreased by 1 cm and it is vibrated with the same tuning fork, 6 beats are heard per second. What is the value of N?
Initial resonance f = N; after shortening from 65 to 64 cm new frequency = N*(65/64), beat frequency = N/64 = 6, so N = 6×64 = 384 Hz.
1052
In some office, there is lot of noise and the sound level of the noise is 80 dB. In order to bring down the sound level to 60 dB, what fraction of present sound level should be kept out or absorbed?
The fundamental note is the lowest frequency produced by a vibrating system.
1057
A light pointer fixed to one prong of a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. Eight complete oscillations are counted when the plate falls through 10 cm. What is the frequency of the tuning fork?
Time to fall 0.10 m is sqrt(2s/g) ≈ 0.1429 s; eight oscillations in that time gives frequency 8 / 0.1429 ≈ 56 Hz.
1058
A source of sound of frequency 165 Hz is placed in front of a wall at a distance of 2 m from it. A detector is also placed in front of the wall at the same distance from it. Find the minimum distance between source and detector for which maximum sound is recorded in the detector. The speed of sound is 330 m/s.
Wavelength λ = v/f = 330/165 = 2 m; constructive maxima occur at separations of integer multiples of λ, so the minimum nonzero distance is 2 m (option B).
