Two rods of the same length, have radii in the ratio `3:4` Their densities are respectively `8000` and `9000 kg//m^(3)`. Their specific heats are in the ratio of `2:3`. When the same amount of heat is supplied to both, the changes in their lengths are in the ratio. (If their linear coefficients are in the ratio `5:6`)

Options

A. `1:1`
B. `5:2`
C. `5:12`
D. `12:5`

Answer

B

Explanation

`Q = msDeltatheta, m = rhopir^(2)l`
`Delta theta = (Deltal)/(lalpha) rArr (Deltal_(1))/(Deltal_(2)) = (rho_(2))/(rho_(1)) xx (r_(2)^(2))/(r_(1)^(2)) xx (s_(2))/(s_(1)) xx (alpha_(1))/(alpha_(2))`