Question

A rectangular loop of wire of size `2.5 cm xx 4 cm` carries a steady current of 1A. A straight long wire carrying 2 A current is kept near the loop as shown. If the loop and the wire are coplanar, find
(i) the torque acting on the loop and
(ii) the magnitude and direction of the force on the loop due to the current carrying wire.

Answer 1

(i) Torque `tau=0`, as there will be forces on the plane of the rectangular coil and wire.
(ii) Forces on the loop `=(mu_(o)I_(1)I_(2))/(2 pi r)` length (Newton)
`= 2xx10^(-7) ((2xx1)/(2xx10^(-2)))xx4xx10^(-2)`
Towards the straight wire,
`=2xx10^(-5)xx(1-(2)/(5))xx4xx10^(-2)=4.8xx10^(-7)` N. towards the straight wire.