Question

A crest of is the point of
(A) Zero displacement
(B) Maximum displacement
(C) Minimum displacement
(D) None of these

Answer 1

We know that when a wave travels, its particle suffers a maximum displacement in the positive or upward direction and also a minimum displacement in downward or negative direction. This is again repeated after a time period.

Complete Step-By Step Answer:
There are various components in a wave. They are:
Amplitude:
Amplitude of the wave is defined as the distance from the equilibrium position and the crest.
Crest:
Crest is defined as the maximum displacement that the particle suffers from the rest position in the upward or positive direction.
Trough:
Trough is defined as the minimum displacement that the particle suffers from the rest position in the upward or positive direction.
Wavelength:
Wavelength of the wave is defined as the distance between two crests.
Time period:
Time period of a wave is defined as the time taken by a wave to complete a full cycle of wave. Thus it is defined as the time taken to complete the distance between two crests and two trough.
Frequency:
Frequency of a wave is defined as the number of waves passing through a point per second. Thus, the frequency is basically reciprocal of time period.
Displacement:
Displacement is defined as the distance that a certain point has moved in the medium.
Thus crest is the point of maximum displacement.

Hence, option (C) is correct.

Note:
Amplitude is basically the distance between the crest and the trough. Amplitude is inversely proportional to frequency. When the crest of the wave increases provided its trough is constant, the amplitude also remains constant.