Two pendulums A and B of length 9m and 16 m, respectively are made to oscillate on the Earth's surface then the ratio of their frequency is ____

Options

A. `3 :4`
B. `9:16`
C. `16 :9 `
D. `4:3`

Answer

D

Explanation

`T prop sqrt(l ) , (T_A)/( sqrt(l_A)) = (T_B)/( sqrt(l_B)) : (T_A)/( T_B) = sqrt((l_A)/(l_B)) = sqrt((9)/(16 )) =3/4`
`T_A : T_B = 3":4 "but" (T_A)/(T_B) = (1//n_A)/( 1// n_B) implies (n_B)/(n_A) = 3//4`