2A current is flowing through a circular coil of radius 10 cm, made of insulated wire and having 100 turns.
If the circular plane of the conductor is kept at right angles to the direction of a magnetic field of `0.2Wb.m^(-2)`, determine the force acting on the coil.

Explanation

Here, `N=100 , R=10 cm=0.1m`
`B=0.2Wb*m^(-2)`.
`:.` Circumference of the circular loop,
`L=2pir=2xx pixx0.1=0.628m`
Area of the circular loop,
`A=pi r^(2)= pi xx(0.1)^(2)=0.0314 m^(2)`
Whole circumference of the conductor is normal to the magnetic field, hence magnetic force
`=NILB=100xx2xx0.628xx0.2=25.12N`
[It should be noted that, in this situation if the circualr plane be tatken as a vector, its direction will be perpendicular to that plane, i.e., parallel to the magnetic field. As a result, no torque will act on the conductor.]