ElectroMagnetic InductionHard
Question
A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1mm/s-1. The induced emf when the radius is 2 cm, is
Options
A.2πμV
B.πμV
C.
D.2μV
Solution
Here,
Magnetic field B = 0.025 T
Radius of the loop, r = 2 cm = 2 × 10-2 cm
Constant rate at which radius of the loop shrinks,
= 1 × 10-3ms-1
Magnetic flux linked with loop is φ = BA cos θ = B(πr2) cos0o = Bπr2
Magnitude of the induced emf is
|ε| =
(Bπr2) = Bπ2r 
= 0.025 × π × 2 × 2 × 10-2 × 1 × 10-3
= π × 10-6 V = πμV
Magnetic field B = 0.025 T
Radius of the loop, r = 2 cm = 2 × 10-2 cm
Constant rate at which radius of the loop shrinks,
= 1 × 10-3ms-1Magnetic flux linked with loop is φ = BA cos θ = B(πr2) cos0o = Bπr2
Magnitude of the induced emf is
|ε| =
(Bπr2) = Bπ2r = 0.025 × π × 2 × 2 × 10-2 × 1 × 10-3
= π × 10-6 V = πμV
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