Q. A 2 amp current is flowing through two different small circular copper coils having radii ratio 1:2. The ratio of their respective magnetic moments will be
A) 1:4
B) 1:2
C) 2:1
D) 4:1
Explanation
[Solution by Claude - not from source] $M=I\pi r^2\propto r^2$, so the ratio is $1:4$. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.