A string of 0.3 m length is found to resonate in 3 segments (nodes at both ends ) when the driving frequency is 20 Hz. The speed of the wave in the spring is :

Options

A. 3 m/s
B. 4 m/s
C. 5 m/s
D. 9 m/s

Answer

B

Explanation

`(3V)/(2l) = 20 `
`V = (20 xx 2l)/(3) = (20 xx 2 xx 0.3)/(3) = 4 ms^(-1)`
Correct choice is (b) .