Q. The magnetic field induction at a point 4 cm from a long current carrying wire is $10^{- 3}$ T. The magnetic field induction at a distance of 1.0 cm from the same current wire will be
A) $2\ \times 10^{- 4}$ T
B) $3\ \times 10^{- 4}$ T
C) $4\ \times 10^{- 3}\ $T
D) $1.11\ \times 10^{- 4}$ T
Explanation
(c) $B_{1}/B_{2} = r_{2}/r_{1}$ or $B_{2} = B_{1}\ r_{1}/r_{2}$
$= 10^{- 3} \times \ $4/1 =$4 \times 10^{- 3}$ T
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.