ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2025

A solenoid of length 0.4 m having 500 turns of wire carries a current of 3 A.
A coil of 10 turns and radius 0.01 m carries a current of 0.4 A.
What will be the torque required to hold the coil in the middle of the solenoid with its axis perpendicular to the axis of the solenoid?

  1. A \( 4.9 \times 10^{-7} \text{ N}\cdot\text{m} \)
  2. B \( 5.9 \times 10^{-6} \text{ N}\cdot\text{m} \)
  3. C \( 3.75 \times 10^{-7} \text{ N}\cdot\text{m} \)
  4. D \( 6.45 \times 10^{-6} \text{ N}\cdot\text{m} \)
Verified Solution

Answer & Solution

Correct Answer

(B) \( 5.9 \times 10^{-6} \text{ N}\cdot\text{m} \)

Step-by-step Solution

Detailed explanation

\( B = \mu_0 \frac{N_s I_s}{L_s} = (4\pi \times 10^{-7}) \frac{500 \times 3}{0.4} = 1.5\pi \times 10^{-3} \text{ T} \) \( M = N_c I_c A_c = N_c I_c (\pi r_c^2) = 10 \times 0.4 \times \pi (0.01)^2 = 4\pi \times 10^{-4} \text{ A}\cdot\text{m}^2 \)…
From CUET
Explore more questions on app