Question

The magnetic induction at any point due to a long straight wire carrying a current is

• A. Proportional to the distance from the wire
• B. Inversely proportional to the distance from wire
• C. Inversely proportional to the square of the distance from the wire
• D. Does not depend on distance

Answer 1

Answer: (B)

Inversely proportional to the distance from wire

Answer 2

$B = \frac { \mu _ { 0 } i } { 2 \pi r }$ or $B \propto \frac { 1 } { r }$