Question

A straight section PQ of a circuit lies along the x-axis from x = – (a/2) to x = + (a/2) and carries a steady current I. The magnetic field due to the section PQ at a point x = +a will be–

• A. Proportional to a
• B. Proportional to a²
• C. Proportional to (1/a)
• D. Equal to zero

Answer 1

Answer: (D)

Equal to zero

Answer 2

Along the wire $\overrightarrow { \mathrm { d } \ell }$ × = 0 **\**dB = 0