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Physics · PYQ NEET UG 2025
हिन्दीA \( 2\text{ amp} \) current is flowing through two different small circular copper coils having radii ratio \( 1:2 \). The ratio of their respective magnetic moments will be
Correct answer · Option 1
1:4
Explanation
Magnetic moment \( M = iA = i(\pi r^2) \). Since current \( i \) is same for both, \( M \propto r^2 \). Therefore, \( \frac{M_1}{M_2} = (\frac{r_1}{r_2})^2 = (\frac{1}{2})^2 = \frac{1}{4} \).
