If a string is stretched with a weight 4 kg then the fundamental frequency is equal to 256 Hz. What weight is needed to produce its octave?

Options

A. 4kg wt
B. 12 kg wt
C. 16 kg wt
D. 24 kg wt

Answer

C

Explanation

`n_1 prop sqrt(T_1) " and " n_2 prop sqrt(T_2)`
`n_2/n_1 = sqrt(T_2/T_1) therefore (n_2/n_1)^2 = T_2/T_1 therefore T_2=4T`
`T_2=T_1xx4`
`m_2g=m_1g4 therefore m_2 = 4xx4 = 16 kg wt`