The fundamental frequency of a sonometer wire increases by 5Hz , if it's tension is increased by 21% . How will the frequency be affected, if its length is increased by 10% ?

Options

A. 55Hz
B. 45.45Hz
C. 40.45Hz
D. 48.32Hz

Answer

B

Explanation

`n_2/n_1=sqrt(T_2/T_1) = sqrt(121/100) = 11/10 = 1.1`
`(n_2-n_1)/(n_1) = 0.1`
`5/n_1 = 0.1 therefore n_1=50Hz`
`(Deltan)/(n_1) = (Deltal)/(l_1) = (l_1-1.1l_1)/(1.1l_1)= (0.1)/(1.1)`
`Deltan = 50 xx1/11 = 4.5`
`n_2 = 45.5 Hz`