Electromagnetic Induction

Equivalent resistance

For maximum power consumption, I should be maximum so denominator is minimum. For this

In case of stretching of wire .
If length becomes 4 times, so resistance becomes 16 times,
ie,

To determine the back electromotive force (emf) induced in a coil, we use the formula involving self-inductance ( ) and the rate of change of current ( ). The formula for the induced emf ( ) is given by:



Where:

• is the induced emf in volts (V).
• is the self-inductance in henrys (H).
• is the rate of change of current in amperes per second (A/s).

For this problem, we have:

Substitute these values into the formula:





The negative sign indicates the direction of the induced emf opposes the change in current (as per Lenz's law), but since we are interested in the magnitude of the back emf, we take:

Magnitude of induced emf,

Therefore, the back emf induced in the coil is 0.88 V.