NEET 2022 — Physics solution

NEET2022Physics

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

A
$12.56 \times 1 0^{- 2}$ T
B
$12.56 \times 1 0^{- 4}$ T
C
$6.28 \times 1 0^{- 4}$ T
D
$6.28 \times 1 0^{- 2}$ T

Solution

For a long solenoid, $B = μ_{0} n I$ where $n$ is the number of turns per unit length.

Here $n = 100$ turns per mm $= \frac{100}{1 0 ^{- 3}}$ turns/m $= 1 0^{5}$ turns/m, and $I = 1$ A.

$B = 4 π \times 1 0^{- 7} \times 1 0^{5} \times 1 = 4 π \times 1 0^{- 2}$ T $\approx 12.56 \times 1 0^{- 2}$ T.

← Back to full paper

Practice more Physics

Concept-wise practice with instant solutions on Fundamenthol.

Start practicing →