An a.c. Generator Consisting Of A Coil Of 100 Turns And Cross-sectional Area Of 3 M2 is Rotating At A Constant Angular Speed Of 60 rad s–1 in A Uniform Magnetic Field Of 0.04 T. The Resistance Of The Coil Is 500 . Calculate Maximum Current Drawn From The Generator, And Power Dissipation In The Coil. From Where Does The Power Come? 

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An a.c. generator consisting of a coil of 100 turns and cross-sectional area of 3 m2 is rotating at a constant angular speed of 60 rad s–1 in a uniform magnetic field of 0.04 T. The resistance of the coil is 500 . Calculate maximum current drawn from the generator, and power dissipation in the coil. From where does the power come? 


Correct option is

518.4 W

The maximum emf induced in the coil is given by  



The maximum current induced in the coil, which can be drawn from the generator is  


The power dissipated as heat in the resistance of the coil is  




              = 518.4 W.  

The induced current causes a torque on the coil opposing its rotation (Lenz’s law). An external agent (a rotor) does work to produce a counter torque to make the coil rotate uniformly. This work is the source of power dissipated in the coil.  




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