There is a pair of fixed, parallel rails of negligible resistance in a horizontal plane, at a distance of L = 10 cm. The rails are connected, at one of their ends to an ideal battery of EMF 0.5 V, as shown in the figure. The system is placed in a vertically downward and perpendicular magnetic field of magnetic induction B = 1T. A metal rod of resistance `R=10Omega` is placed perpendicularly on the rails. The rod placed perpendicularly on the rails. The rod and rails are frictionless. The magnitude of force, which is to be exerted on the rod in order to move it with a constant speed of order to move it with a constant speed of `1ms^(-1)` in the direction shown, is

Options

A. `2xx10^(-3)N`
B. `4xx10^(-3)N`
C. `8xx10^(-3)`
D. `5xx10^(-3)N`

Answer

B