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Electric Charges And Fields

Question
CBSEENPH12037872

A coil of number of turns N, area A, is rotated at a constant angular speed ω, in a uniform magnetic field B, and connected to a resistor R. Deduce expressions for:
(i)    maximum emf induced in the coil.
(ii)    power dissipation in the coil.

Solution

Given, a coil of N turns having an area A, rotated with angular speed 'ω'  in a uniform magnetic field 'B' connected to a resistor 'R' .
 
The flux linking to the coil,  ϕ = NBA sin (ωt) 
Therefore,
Induced EMF, E = dNBA cos ωtdt    = NBA ω sin ωt  

When, sinωt = ±1, the induced emf value is maximum. 

(i) The maximum EMF, E0 = NBA ω 

(ii) The power dissipated in the coil is given by,  
                 P= E2rmsR   = E022R   = (NAB ω)22R