A telegraph wire of length 2500m, is kept in E-W direction, at a height of 10 m from the ground. If it falls freely on the ground, then the current induced in the wire is _______. [Given : Resistance of the wire = `25 sqrt(2) Omega, g=10 m//s^(2) and B_(H)= 2 xx 10^(-5) T`]

Options

A. 6.1 A
B. 0.01 A
C. 0.02 A
D. 0.2 A

Answer

C

Explanation

`e = B_(H)lV = B_(H)lsqrt(2gh)`
The velocity V is given by `V^(2) = 2gh`
We get `e = 50sqrt(2) xx 10^(-2)V`
`:. I = e/R = (50 xx 1.414 xx 10^(-2))/(35) = 0.02 A`.