Question

A coil with a self-inductance of 6.50 H carries a current that is changing at a rate of 50.0 A/s.

What is the induced emf in the coil?

Answer 1

Induced emf is given by

$\epsilon =-L\frac{di}{dt}$

Induced emf of coil can not be negetive so rate of change in current should be negetive.

By putting value

$\epsilon=(-6.50) (-50.0) \\\epsilon=325.0V$