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Question
A metal rod `1/sqrtpi `m long rotates about one of its ends perpendicular to a plane whose magnetic induction is 4 x 10-3 T. Calculate the number of revolutions made by the rod per second if the e.m.f. induced between the ends of the rod is 16 mV.
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Solution
`L=1/sqrtpim="radius"`
B = 4x10-3T
e = 16mv
=16x10-3v
Area covered in one revolution
A=πL2
`=pi(1/sqrtpi)^2`
=1m2
e=BfA
`:.f=e/(BA)`
`=(16xx10^(-3))/(4xx10^(-3)xx1)`
f=4Hz
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