Question

A wave in a string has an amplitude of `2 cm`. The wave travels in the `+ve` direction of x axis with a speed of 1`28 ms^-1` and it is noted that `5` complete waves fit in `4 m` length of the string. The equation describing the wave is
A. y = (0.02)m sin (7.58x – 1005 t)
B. y = (0.02)m sin (7.85x + 1005 t)
C. y = (0.02)m sin (15.7x – 2010 t)
D. y = (0.02)m sin (15.7x + 2010 t)

Answer 1

Correct Answer - A
`5 lambda=4 `
` lambda=(4)/(5)`
`k=(2 pi)/ lambda=(10pi)/(4)=7.85`
wave moves along positive X-direction