A wave frequency `100 Hz` travels along a string towards its fixed end . When this wave travels back after reflection , a node is formed at a distance of `10 cm `from the fixed end . The speed of the wave (incident and reflected) is

Options

A. 5 m/s
B. 20 m/s
C. 10 m/s
D. 40 m/s

Answer

D

Explanation

Speed = frequency `xx` wavelength
Distance between consecutive nodes is `lambda//2`.
`therefore (lambda)/(2)=10cmorlambda=20cm`
`therefore` Speed = `100xx20=2000 cm//s=20m//s`