Q. A solenoid of 1.5 m length and 4.0 cm diameter has 10 turns per cm. A current of 5 A is flowing through it. The magnetic field induction at axis inside the solenoid is
A) $2\pi\ \times 10^{- 4}\ $T
B) $2\pi\ \times 10^{- 5}\ $T
C) $20\ \pi\ G$
D) $2\ \pi\ G$
Explanation
(c) $B = \ \mu_{0}\ ni = 4\pi \times 10^{- 7} \times (100 \times 100) \times 5$
$= 2\pi \times 10^{- 3}\ T = 2\pi\ \times 10^{- 3} \times 10^{4}\ G = 20\pi G.$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.