Electro Magnetic Induction And Alternating Currents Question 306

Question: A copper rod of length l is rotated about one end perpendicular to the magnetic field B with constant angular velocity ω . The induced e.m.f. between the two ends is [MP PMT 1992; Orissa JEE 2003]

Options:

A) 12Bωl2

B) 34Bωl2

C) Bωl2

D) 2Bωl2

Show Answer

Answer:

Correct Answer: A

Solution:

If in time t. the rod turns by an angle q, the area generated by the rotation of rod will be

=12l×lθ =12l2θ

So the flux linked with the area generated by the rotation of rod

φ=B (12l2θ)cos0=12Bl2θ=12Bl2ω,t

And so e=dφdt=ddt(12Bl2ωt)=12Bl2ω



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