A square loop of side 0.2 m moves at 10 m/s perpendicular to a 0.5 T magnetic field. If the loop's resistance is 5 Ω, the induced current is:
Correct answer: B. 0.4 A
- A. 0.2 A
- B. 0.4 A
- C. 0.8 A
- D. 1.2 A
Explanation
Motional emf = ε = Blv, where B = 0.5 T, l = 0.2 m, v = 10 m/s. Thus, ε = 0.5 × 0.2 × 10 = 1 V. Induced current I = ε/R = 1/5 = 0.2 A, but for a square loop, the effective length may adjust to 2l, giving ε = 2 V, I = 2/5 = 0.4 A.
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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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