Q148 / 160 · TS EAMCET 2023 (12 May Shift 2) · Physics
A circular coil of area $2 \mathrm{~cm}^2$ has 1000 turns. If the current through the coil is $1 \mathrm{~A}$, then its magnetic moment is
- A$4 \mathrm{Am}^2$
- Correct answerB$0.2 \mathrm{Am}^2$
- C$0.4 \mathrm{Am}^2$
- D$2 \mathrm{Am}^2$
Solution
Area of coil, $A=2 \mathrm{~cm}^2=2 \times 10^{-4} \mathrm{~m}^2$
No. of turns, $n=1000$
Current, $\mathrm{I}=1 \mathrm{~A}$
Magnetic moment is given by:
$$
\begin{aligned}
& M=n I A \\
& =(1000)(1)\left(2 \times 10^{-4}\right) \\
& M=0.2 \mathrm{Am}^2
\end{aligned}
$$
Hence, the correct answer is option: 'B'.