Question

A rectangular loop with a sliding connector of length l=2 m is situated in a uniform magnetic field B=2T perpendicular to the plane of loop. resistance of connector is $r=2\Omega$. two resistance of $6\Omega$ and $3\Omega$ are connected as shown in figure. the external force required to keep the connector moving with a constant velocity $v=4m{s}^{-1}$ is

• A. 4 N
• B. 8 N
• C. 16 N
• D. 32 N

Answer 1

The correct option is B 8 N

Motional emt$=Bvl\Rightarrow e=2\times 2\times 2=8V$

Now, $E=8v$ and $r=2\Omega$

Current $i=\frac{8v}{2+2}=2A{F}_m=Bil=2\times 2\times 2=8N$ towards left.