Question

give the expression for energy stored in a coil

Answer 1

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Answer 2

ever current flows through coil this is difference opposes the growth of current in some work has to be done by the external agencies in stabilizing the current .

If e is the induced emf, then ,

e= -L dI/dt

Where L is the self inductance of the coil

small amount of work done dW in a time interval dt the rate of work done is given by:

dW/dt =|e| I

dW/dt = L dI/dt . I

dW/dt = LI dI/dt

The total amount of work done in establishing current is given by integrating the above equation

Then see the picture for the rest.