Question

A rectangular loop of wire of size `2 cm xx 5cm ` carries a steady current of 1A. A straight long wire carrying 4 A current is kept near the loop as shown. If the loop and the wire are coplanar, find
(i) the torque acting on the end
(ii) the magnitude and direction of the force on the loop due to the current carrying wire.

Answer 1

(i) Torque `tau=0`, as net acting on the coil is zero.
(ii) Forces on the loop `=(mu_(o)I_(1)I_(2))/(2pi r)` length (Newton)
`=2xx10^(-3)((4xx1)/(1xx10^(-2))-(4xx1)/(3xx10^(-2)))xx5xx10^(-2)`
towards the straight wire,
`=2xx10^(-5)xx(4-(4)/(3))xx5xx10^(-2)`
`=(80)/(3)xx10^(-7)` N. towards the straight wire.