A square loop of side a hangs from an insulating hanger of spring balance. The magnetic field of strength B occurs only at the lower edge. It carries a current I. Find the change in the reading of the spring balance if the direction of current is reversed.

Question

A square loop of side a hangs from an insulating hanger of spring balance. The magnetic field of strength B occurs only at the lower edge. It carries a current I. Find the change in the reading of the spring balance if the direction of current is reversed. (A) I a B (B) 2 I a B (C) (I a B/2) (D) (3/2) I a B

Tardigrade Admin · Accepted Answer

Initially F1+m g+I a B (downwards) When the direction of current is reversed F2=m g=-I a B (downwards) ⇒ Δ F=2 I a B

Q. A square loop of side a hangs from an insulating hanger of spring balance. The magnetic field of strength $B$ occurs only at the lower edge. It carries a current $I$ . Find the change in the reading of the spring balance if the direction of current is reversed.

$I a B$

$2 I a B$

$\frac{I a B}{2}$

$\frac{3}{2} I a B$

Initially $F_{1} + m g + I a B$ (downwards)
When the direction of current is reversed
$F_{2} = m g = - I a B$ (downwards)
$\Rightarrow Δ F = 2 I a B$

Q. A square loop of side a hangs from an insulating hanger of spring balance. The magnetic field of strength B occurs only at the lower edge. It carries a current I. Find the change in the reading of the spring balance if the direction of current is reversed.

IaB

2IaB

2IaB​

23​IaB