A wire of mass 5 gram is kept stretched by a force of 400 N. When plucked at a point, transverse waves travel along the wire with a speed of 400 m/s. The length of the wire is

Options

A. 1 m
B. 2 m
C. 3 m
D. ` 1.5` m

Answer

B

Explanation

`V = sqrt(T/m) " " :. V^(2) = T/ m " " :. m = T/ V^(2)`
` :. (5 xx 10^(-3))/ L = 400/(400 xx 400) = 1/ 400 `
` :. L = 400 xx 5 xx 10 ^(-3) = 2 `m