Question

$PQRS$ is a square loop made of uniform conducting wire. If the current enters the loop at $P$ and leaves at $S$, then the magnetic field will be

• A. Maximum at the centre of the loop
• B. Zero at the centre of loop
• C. Zero at all ppoints in side the loop
• D. Zero at all points outside of the loop

Answer 1

The correct option is A Maximum at the centre of the loop

Resistance of $(PQ+QR+RS)=3$ Resistance of $\left(AD\right)$

$i_1=i_4,i_2=3i_4$

At O. Magnetic field due to $(PQ+QR+RS)$ is equal and opposite to magnetic field due to $\left(AD\right)$

$B_O=0$

The magnetic field is zero at all the points outside the loop.