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An elastic conducting material is stretched into a circular loop of 14.8 cm radius. It is placed with its plane perpendicular to a uniform 0
Question
An elastic conducting material is stretched into a circular loop of 14.8 cm radius. It is placed with its plane perpendicular to a uniform 0.814 T magnetic field. When released, the radius of the loop starts to shrink at an instantaneous rate of 88.4 cm/s. What emf is induced in volts in the loop at that instant
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Physics
4 years
2021-08-03T10:08:28+00:00
2021-08-03T10:08:28+00:00 1 Answers
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Answers ( )
Answer: 0.666 V
Explanation:
Given
Radius of the loop, r = 14.8 cm = 0.148 m
Magnetic field present, B = 0.814 T
Rate of shrinking, dr/dt = 88.4 cm/s = 0.884 m/s
emf = dΦ/dt , where Φ = BA
emf = d(BA)/dt, where A = πr²
emf = d(Bπr²)/dt
if B is constant, then
emf = Bπ d(r²)/dt, on differentiating, we have,
emf = Bπ * 2r dr/dt
emf = 2πrB dr/dt, now if we substitute the values, we have
emf = 2 * 3.142 * 0.148 * 0.814 * 0.884
emf = 6.284 * 0.106
emf = 0.666 V