Two different wire A and B of same cross sectional area are joined to form a composite wire of length 1.5m of which wire A is 0.6 m and the rest is wire B. The densities of A and B are in the ratio 1:4 when the joint in the wire is a node , then the number of loops formed in A and B are in the ratio

Options

A. `2:3`
B. `3:2`
C. `1:2`
D. `1:3`

Answer

D

Explanation

`l_1=0.6, l_2 = 0.9 , rho_1/rho_2 = 1/4 , P_1/P_2 = ?`
`n_1 = n_2`
`P_1l_1 sqrt(T/rho_1) = P_2/l_2sqrt(T/rho_2)`
`P_1/P_2 = l_1/l_2 sqrt(rho_1/rho_2`
`=(0.6)/(0.9) xx sqrt(1/4) = 2/3xx1/2 = 1/3`