A circular loop of radius 0.2 m is placed in a magnetic field of 0.8 T. If the loop is rotated by 90° in 0.1 s, the average induced emf is:
Correct answer: B. 8.04 V
- A. 4.02 V
- B. 8.04 V
- C. 16.08 V
- D. 32.16 V
Explanation
Induced emf = ε = NΔΦ/Δt, where Φ = BA cosθ, A = π(0.2)² = 0.1256 m², Δcosθ = (cos 0° - cos 90° = 1), B = 0.8 T, Δt = 0.1 s, N = 1. Thus, ΔΦ = 0.8 × 0.1256 = 0.1005 Wb, ε = 0.1005/0.1 = 8.04 V.
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Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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