Question

The magnetic induction at any point due to a long straight wire carrying a current is [MP PMT/PET 1998]
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

Hii friend,

Here is your answer.......


The magnetic induction at any point due to a long straight wire carrying a current is defined by the formula,


B=μ0I / 4πa

B=μ0I / 4πa [sinϕ2+sinϕ1]

The wire is straight long so it is perpendicular in position and angle is at 90°

:-
B => μ0I/ 4πa.

where,

B => magnetic induction
a => perpendicular length.

B is inversely proportional to "a"

:-The answer is option "B"

magnetic induction is inversely proportional to the distance of the wire.

Hope this helps you a little!!!