NEET 2025
- Exam
- NEET
- Year
- 2025
- Subject
- Physics
- Chapter
- Magnetic Effects of Current
NEET 2025 · Physics · Magnetic Effects of Current
A 2 amp current is flowing through two different small circular...
A 2 amp current is flowing through two different small circular copper coils having radii ratio . The ratio of their respective magnetic moments will be
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
\begin{aligned}
&\text{ Magnetic moment } \mathrm{M}=\mathrm{I}(\mathrm{ A})\\
&\begin{aligned}
& \mathrm{M}=\mathrm{I}\left(\pi \mathrm{r}^2\right) \\
& \frac{\mathrm{M}_1}{\mathrm{M}_2}=\frac{I \pi r_1^2}{I \pi r_2^2}=\left(\frac{r_1}{r_2}\right)^2=\left(\frac{1}{2}\right)^2 \\
& \frac{\mathrm{M}_1}{\mathrm{M}_2}=\frac{1}{4}
\end{aligned}
\end{aligned}$