    Question

# A coil of resistance 40 Ω is connected to a galvanometer of 160Ω resistance. The coil has radius 6 mm and turns 100. this coil is placed between the poles of a magnet such that magnetic field is perpendicular to coil is dragged out then the charge through the galvanometer is 32μC. The magnetic field is:

A
6.55 T
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B
5.66 T
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C
0.655 T
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D
0.566 T
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Solution

## The correct option is D 0.566 TGiven,Total charge flow, Q=32×10−6C Total resistance, R=160+40= 200Ω Number of turns, N=100 radius of coil, r=6mm=6×10−3m ε=−Ndϕdt Rdqdt=−NBdAdt for limiting values ⇒RQtotalΔt=−NBΔAΔt ⇒RQtotal=−NB(0−πr2) ⇒B=RQtotalNπr2=200×32×10−6100×π×0.0062=0.566 T Hence, the Magnetic Field is 0.566 T  Suggest Corrections  0      Related Videos   PHYSICS
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