The expression for induced EMF in the rotating loop in uniform magnetic field is given by
ϵ=NABωcosωt
The average power loss
<P>=<Rϵ2>=<RA2B2ω2cos2ωt>
<cos2θ>=21
<P>=RA2B2ω2(21)
⇒<P>=2Rπ2a2b2B2(ω2)
JEE Main 2020 — Physics Electromagnetism
An elliptical loop having resistance R, of semi major axis a , and semi minor axis b is placed in a magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency ω, the average power loss in the loop due to Joule heating is :

Held on 3 Sept 2020 · Verified 6 Jul 2026.
2Rπ2a2b2B2ω2
zero
RπbBω
Rπ2a2b2B2ω2
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