Question

A rectangular coil of length $10cm$ and breadth $20cm$ is placed in uniform magnetic field of induction $20Wb{m}^{-2}$ . A current of $2A$ is passed through the coil. If it consists of $100$ turns, the maximum torque experienced is :

• A. $40Nm$
• B. $80Nm$
• C. $4000Nm$
• D. $8000Nm$

Answer 1

The correct option is B $80Nm$

$J=niAB\sin \theta$
maximum at ,
$\sin \theta =1$
$\therefore J=niAB=100\times 2\times 20\times 10\times 20\times {10}^{-4}=80Nm$