2022 Moving Charges and MagnetismMagnetic Field of a Solenoid Easy Question 1 of 3 in Magnetic Field of a Solenoid

A long solenoid of radius 1 mm has 100 turns per mm. If 1 A current flows in the solenoid, the magnetic field strength at the centre of the solenoid is :

A $6.28\times10^{-4}\ T$
B $6.28\times10^{-2}\ T$
C $12.56\times10^{-2}\ T$
D $12.56\times10^{-4}\ T$

The answer is C.

Solution

$B = \mu_0 n i = \mu_0\frac{N}{\ell}i$ $n = 100$ turns per mm $= \frac{100}{10^{-3}}$ turns per m $B = 4\pi \times 10^{-7} \times \frac{100}{10^{-3}} \times 1 = 12.56 \times 10^{-2}$ T

Concept B = μ0 n I

Magnetic Field of a Solenoid in past papers

3 questions from this chapter have appeared across 3 exam years.