Question

Figure (15-E2) shows a plot of the transverse displacements of the particles of a string at t = 0 through which a travelling wave is passing in the positive x-direction. The wave speed is $20cm{s}^{-1}$. Find (a) the amplitude, (b) the wavelength, (c) the wave number and (d) the frequency of the wave.

Answer 1

Given that, v = 20 cm/s

(a) Amplitude, A = 1 mm

(b) Wavelength, $\lambda =4mm$

(c) Wave number, $n=\frac{2\pi }{\lambda }$

$=\frac{(2\times 3.14)}{4}$

$=1.57c{m}^{-1}$

(wave number = k)

(d) Frequency, $f=\frac{1}{T}=\frac{20}{4}=5Hz$

(where time period $T=\frac{\lambda }{v}$)