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 20 cm s−1. Find (a) the amplitude, (b) the wavelength, (c) the wave number and (d) the frequency of the wave.
Figure

Answer 1

Frequency is 5 Hertz

Explanation:

Given,  

Wave speed, v = 20 cm/s

From the graph, we can infer-  

(a) Amplitude, A = 1 mm

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

(c) Wavenumber, $k = \frac {2\pi}{\lambda}$

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

= $1.57 cm^-^2$

(d) Time Period, T = $\frac {\lambda}{v}$

Frequency, f = $\frac {1}{T} = \frac {v}{\lambda}$

So, f = $\frac {20}{4}$ = 5 Hz

*Kindly refer attached figure