Answer :
The time for the crest of a wave having a frequency of 810 hz, a wavelength of 0.40 m, and an amplitude of 4.0 mm to travel to the closest length of wire is 19 ms.
Wavelength
Wavelength is the distance between one wave frequency peak and another peak. Therefore, the wavelength of frequency is the distance that a wave must travel in one period. This wavelength is denoted by the symbol λ (lambda) with units of m (meters).
the equation between wavelength, speed and frequency is:
λ = v/f
We have,
Wavelength = 0.4 m ⇒ λ
Frequency = 810 hz ⇒ f
Distance = 6.0 m
And, the velocity:
v = λ x f
= (0.4) (810)
= 324 m/s
So, the time for a crest of this wave to travel the length of the wire is closest to:
time = distance/velocity
= 6/324
= 0.0185 s = 19 ms.
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