Q. A uniform conducting wire of length 12 a and resistance 'R' is wound up as a current carrying coil in the shape of, i. an equilateral triangle of side 'a'. ii. a square of side 'a'. The magnetic dipole moments of the coil in each case respectively are:
A) 3 $Ia^2$ and $Ia^2$
B) 3 $Ia^2$ and 4 $Ia^2$
C) 4 $Ia^2$ and 3 $Ia^2$
D) $\sqrt{3}\ Ia^2$ and 3 $Ia^2$
Explanation
[Solution] Triangle: 4 turns × $\frac{\sqrt{3}}{4}a^2$ gives $\sqrt{3}Ia^2$. Square: 3 turns × $a^2$ gives $3Ia^2$. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.