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Question
A magnetic field of 2×10−2 T acts at right angles to a coil of area 100 cm2, with 50 turns. The average e.m.f. induced in the coil is 0.1 V, when it is removed from the field in t sec. The value of t is
A magnetic field of 2×10−2 T acts at right angles to a coil of area 100 cm2, with 50 turns. The average e.m.f. induced in the coil is 0.1 V, when it is removed from the field in t sec. The value of t is
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Solution
The correct option is B 0.1 s
By Lenz's law,
e=−(ϕ2−ϕ1)tϕ2=0, as no field lines will pass through the coil after time t=−(0−NBA)t=NBAtSo, t= NBAe= 50×2×10−2×10−20.1=0.1 s
By Lenz's law,
e=−(ϕ2−ϕ1)tϕ2=0, as no field lines will pass through the coil after time t=−(0−NBA)t=NBAtSo, t= NBAe= 50×2×10−2×10−20.1=0.1 s