A square loop of side 0.1 m with 40 turns is placed in a magnetic field of 0.5 T. If the field is reversed in 0.02 s, the average induced emf is:
Correct answer: B. 40 V
- A. 20 V
- B. 40 V
- C. 80 V
- D. 100 V
Explanation
Induced emf = ε = NΔΦ/Δt, where Φ = BA, A = 0.1 × 0.1 = 0.01 m², ΔB = 0.5 - (-0.5) = 1 T, N = 40, Δt = 0.02 s. Thus, ΔΦ = 1 × 0.01 = 0.01 Wb, ε = 40 × 0.01/0.02 = 40 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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