A metallic rod completes its circuit as shown in the figure. The circuit is normal to a magnetic field of `B=0.15` tesla. If the resistances of the rod is `3Omega` the force required to move the rod with a constant velocity of `2m//sec` is-

Options

A. `3.75 xx 10^(-3) N`
B. `3.75 xx 10^(-2) N`
C. `3.75 xx 10^2 N`
D. `3.75 xx 10^(-4) N`

Answer

A

Explanation

`V = Bvl = 0.15 xx 2 xx 0.5 = 0.15 xx 1`
`= 0.15 ` volt
`F = Bil = 0.15 xx (0.15)/3 xx 0.5`
` = 375 xx 10^(-2) = 3.75 xx 10^(-2)`