Question

A conducting circular loop is placed in a uniform magnetic field of 0.04T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2mm s⁻1. The induced emf in the loop when the radius is 2cm is:

• A. \(4.8\,\pi\,\mu\text{V}\)
• B. \(0.8\,\pi\,\mu\text{V}\)
• C. \(8\,\pi\,\mu\text{V}\)
• D. 16πμV

Hint:

For shrinking loop: E=2π Br(dr)/(dt).

Answer 1

The Correct Option is A

Step 1: Magnetic flux: Φ=BA=π Br²
Step 2: Induced emf: E=|(dΦ)/(dt)|=2π Br(dr)/(dt)
Step 3: Substituting values: E=2π(0.04)(0.02)(2×10⁻3) =4.8πμV