Question

If a tuning produces 5 beat/s with a sonometer wire of lengths 40cm and 44cm , other factor remaining unchanged, then the frequency of the tuning fork will be
A. 80Hz
B. 88Hz
C. 100Hz
D. 105Hz

Answer 1

Correct Answer - D
The frequency of the sonometer wire is n which is in between `n_1 " and " n_2 therefore n_1 gt n gt n_2`
`therefore n_1-N = 5 " and " N-N_2=5`
`n_1l_1=n_2l_2`
`n_1/n_2=l_2/l_1=44/40=11/10=1.1`
`n_1=1.1n_2`
`1.1n_2-n_2 = 10 therefore 0.1n_2 = 10`
`therefore n_2=100`
`therefore n=n_2+5=100+5=105Hz`