Question

Two thick wires and two thin wires, all of same material and same length, form a square in three different ways $P, Q$ and $R$ as shown in the figure. With correct connections shown, the magnetic field due to the current flow, at the centre of the loop will be zero in case of...........

• A. P and Q only
• B. P and R only
• C. Q and R only
• D. P only

Answer 1

Answer: (B)

P and R only

Answer 2

In $P$ and $R$, current divides equally in two halves because of equal resistances in the two halves. Due to equal currents in two halves the current at the centre will be zero.