A square metallic wire loop of side `0.1 m` and resistance of `1W` is moved with a constant velocity in a magnetic field of `2wb//m^(2)` as shown in figure. The magnetic field field is perpendicular to the plane of the loop, loop is connected to a network of resistances. what should be the velocity of loop so as to have a steady current of `1mA` in loop?

Options

A. `1 cm//sec`
B. `2 cm//sec`
C. `3 cm//sec`
D. `4 cm//sec`

Answer

B

Explanation

Equivalent resistance of the given wheatstone bridge circuit (balanced) is `3W` so total resistance in circuit is `R=3+1=4Omega`. The emf induced in the loop `e=Bvl`.
so induced current `i=(e)/(R )=(Bvl)/(R )`
`implies 10^(-3)=(2xxvxx(10xx10^(-2)))/(4)=v=2cm//sec`.