A 200 turns closely wound circular coil of radius 10 cm carries a current of 3.5 A. The magnetic moment of the coil is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → $22\, A m^2$
$n = 200,\; r = 10 \text{ cm} = 0.1 \text{ m},\; I = 3.5$
$A = \pi r^2 = \pi (0.1)^2 = 0.01\pi$
$\mu = nIA$
$\mu = 200 \cdot 3.5 \cdot 0.01\pi$
$\mu = 7\pi$
$\mu \approx 22$
Final Answer: $22 \text{ A·m}^2$