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

Options

A. `y=(0.02)m sin (15.7x+2010t)`
B. `y=(0.02)m sin (15.7x+2010t)`
C. `y=(0.02)m sin (7.85x+1005t)`
D. `y=(0.02)m sin (7.85x+1005t)`

Answer

C

Explanation

At = 2cm , `omega /k=128 ms^-1,5 lamda=4, lamda= 4/5m`
`y=A sin (kx- omega t)`
`k=(2 pi )/lamda=(2 pi times 5)/4=31.4/4=7.85`
`y=0.02 m sin (7.857-1005 t)`
`omega =128 times 7.85=1005`