Q. A long solenoid of length $L$ has a mean diameter $D.$ It has $n$ layers of winding of $N$ turns each. If it carries a current $I,$ the magnetic field at its centre will be
A) Proportional to $D$
B) Inversely proportional to $D$
C) Independent of $D$
D) Proportional to $L$
Explanation
(c) Magnetic field due to solenoid is independent of diameter
$\left( \because B = \mu_{0}\ nI \right)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.