Question

A copper wire is held at two ends by rigid supports. At `40^@C`, the wire is just taut with negligible tension . The speed of transverse wave in the wie at `10^@C` is
`(alpha=7xx10^(-4)//^@C, y=2.1xx10^11 N//m^2, "density"=9000kg//m^3)`
A. 491m/s
B. 79m/s
C. 700m/s
D. 49.1m/s

Answer 1

Correct Answer - C
`v=sqrt(T/m) = sqrt((yAl)/(LrhoA)) = sqrt((ypropDeltat)/(rho))`
`=sqrt((2.1xx10^11xx7xx10^(-4)xx30)/(9xx10^3))`
`=sqrt((0.7xx7xx30xx10^4)/(3)) = sqrt(49xx10^4)`
`700m//s`