a circular ring of diameter 20 cm has a resistance 0.01 ohm. The ring is turned from a position perpendicular to a magnetic field of 2 T to a position parallel to the field. The amount of charge flowing through the ring in the process is?
Area of ring = pi*r2 = 3.14 x 0.1 x 0.1 = 0.0314 m2
When ring is perpendicular to field, the area under the field is 0.0314 m2 and when it is parallel to the field, area under the field is 0
Change in flux = magnetic field x change in area = 2 x 0.0314 - 0 = 0.0628 weber
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induced emf = change in flux / time
I x R = change in flux / t
(q/t) x R = change in flux / t
q x R = change in flux
q = change in flux / R = 0.0628 / 0.01 = 6.28 C