Question

A current of 1 ampere is passed through a straight wire of length 2.0 metres. The magnetic field at a point in air at a distance of 3 metres from either end of wire and lying on the axis of wire will be

• A. $\frac { \mu _ { 0 } } { 2 \pi }$
• B. $\frac { \mu _ { 0 } } { 4 \pi }$
• C. $\frac { \mu _ { 0 } } { 8 \pi }$
• D. Zero

Answer 1

Answer: (D)

Zero

Answer 2

The magnetic field at any point on the axis of wire be zero.