A circular loop of radius 0.1 m carries a current of 2 A. Calculate the magnetic field at its centre and state the direction of the field if the current flows clockwise.

medium 3 marks Class 12 · Physics · Magnetism and Matter

Answer

2.00 \times 1 0^{- 5}, T

, directed into the page.

The correct answer is $2.00 \times 1 0^{- 5}, T$ , directed into the page. — Use the right‑hand rule: for a clockwise current, the field at the centre points into the page.

Step-by-step solution

The magnetic field at the centre of a circular loop is $B = \frac{μ _{0} I}{2 R}$ .
Insert $μ_{0} = 4 π \times 1 0^{- 7}, H/m$ , $I = 2, A$ and $R = 0.1, m$ to obtain $B = \frac{4 π \times 1 0 ^{- 7} \times 2}{2 \times 0.1} = 2.00 \times 1 0^{- 5}, T$ .
Use the right‑hand rule: for a clockwise current, the field at the centre points into the page.

Common mistake: Forgetting the factor 2 in the denominator

Concept tested: Magnetic field of a circular current loop

Published 5 September 2026 · Last updated 16 September 2026 · How this solution was prepared and checked

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