Question

A solenoid of 1.5 m length and 4.0 cm diameter
possesses 10 turns/cm. A current of 5 A is flowing
through it. The magnetic induction at axis inside the
solenoid is

• A. $2 \pi \times 10^{-3}T $
• B. $2 \pi \times 10^{-5}T $
• C. $2 \pi \times 10^{-3}G $
• D. $2 \pi \times 10^{-5}G $

Answer 1

Answer: (A)

Magnetic field B $= \mu _0ni $
$ =4 \pi \times 10^{-7} \times 5 \times 1000 $
$ = 2 \pi \times 10^{-3} T $