The massses of the three wires of copper are in the ratio 1 : 3 : 5. And their lengths are in th ratio 5 : 3 : 1. the ratio of their electrical resistance is

Options

A. `1:3:5`
B. `5:3:1`
C. `1:15:125`
D. `125:15:1`

Answer

D

Explanation

`R prop (l^(2))/(m) rArr R_(1):R_(2):R_(3)=(l_(1)^(2))/(m_(1)): (l_(2)^(2))/(m_(2)):(l_(3)^(2))/(m_(3))`
`=(25)/(1):(9)/(3):(1)/(5)=25:3:(1)/(5)`
`R_(1):R_(2):R_(3)=125:15:1`