Q. A coil of wire of a certain radius has 600 turns and a self inductance of $108\ mH$. The self inductance of a 2$^{nd}$ similar coil of 500 turns will be
A) $74\ mH$
B) $75\ mH$
C) $76\ mH$
D) $77\ mH$
Explanation
(b) $\frac{L_{B}}{L_{A}} = \left( \frac{n_{B}}{n_{A}} \right)^{2} \Rightarrow L_{B} = \left( \frac{500}{600} \right)^{2} \Rightarrow 108 = 75\ mH$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.