Question

A sonometer wire of length `1.5m` is made of steel. The tension in it produces an elastic strain of `1%`. What is the fundamental frequency of steel if density and elasticity of steel are `7.7 xx 10^(3) kg//m^(3)` and `2.2 xx 10^(11) N//m^(2)` respectively ?
A. 188.5 Hz
B. 178.2 Hz
C. 200.5 Hz
D. 770 Hz

Answer 1

Correct Answer - B
Fundamental frequency
`f=(V)/(2l)=(1)/(2xx1.5)sqrt((T)/(eq))=(1)/(3)sqrt((yxx"strain" xxS)/(rho S))`
(S `rarr` cross - section Area)
`= =(1)/(3)sqrt((2.2xx10^(11)xx(1)/(100))/(7.7xx10^(3)))=178.2Hz`