Find the incorrect from the following the equation of a stationary wave is given by `y=6cos((pix)/(5))sin(4pit)`, where y and x are in cm and t is in second. Then, for the stationary wave

Options

A. amplitude=3cm
B. wavelength=5cm
C. frequency=20Hz
D. velocity=2m/s

Answer

B

Explanation

Given, `y=6cos((pix)/(5))sin(40pit)`
Comparing with
`y=2Acos((2pix)/(lamda))sin((2pit)/(T))`
we get, A=3 cm, `2pint=40pit`
`therefore`v=20Hz`
`(2pix)/(lamda)=(pix)/(5)`
`thereforelamda=10cm`
and `v=vlamda=20xx10=2m//s`
`[lamda=5cm` is wrong].