A metal rod `40 cm` long is dropped on to a wooden floor and rebounds into air . Compressional waves of many frequencies are thereby set up in the rod . If the speed of compressional waves in the rod in `5500 m//s`, what is the lowest frequency of compressional waves to which the rod resonates as it rebounds?

Options

A. `675 Hz`
B. `6875 Hz`
C. `16875 Hz`
D. `0 Hz`

Answer

B

Explanation

`(lambda)/(2) = l = (40)/(100) = 0.4 , lambda = 0.8 m`,
`v = (v)/( lambda) = ( 5500)/(0.8) Hz = 6875 Hz`