Multiple choice

A circular coil of 100 turns and an area of 10 cm2 rotates about a diameter with an angular velocity 100 rad/s in a uniform magnetic field of 0.10 T. The axis of rotation is perpendicular to the field. The coil has a resistance of 10Ω. The emf induced in the coil is supplied to an external resistance of 10 ohm. Calculate the peak current flowing through the external resistance.

  1. 20 A

  2. 0.05 A

  3. 5 A

  4. 0.2 A

  5. 2000 A
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Peak emf is given byε0 = NBAω N = 100, B = 0.10 T, A = 10 cm2 = 10 x 10- 4 m2, ω = 100 rad/s So, ε0 = NBAω = 100 x 0.10 x 10 x 10- 4 x 100 = 1 V . Peak current through the external resistance = ε0 / (10 + 10) = 1/20 = 0.05 A.

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