Question

Calculate the torque on a `200` turns rectangular coil of length `20cm` and breadth `10cm` carrying a current of `10A`, when placed in a magnetic field. The plane of the coil is making an angle of `60^@` with a magnetic field of `4T`.

Answer 1

Correct Answer - `80N-m`
Here, `n=200`, `l=20cm=0*20m`,
`b=10cm=0*10m`
`B=4T`, `A=lxxb=0*20xx0*10=0*02m^2`,
`I=10A`.
Angle between `vecB` and normal on the plane of the coil `theta=90^@-60^@=30^@`
Torque, `tau=nIBA sin theta`
`=200xx10xx4xx0*02xxsin30^@=80N-m`