Question

The current passing through a core coil of 5 is decreasing at the rate of 2 ampere per second the emf developed across the coil is

Answer 1

Answer:

The given question is incomplete.

Correct Question: The current passing through a choke coil of 5 henry is decreasing at the rate of 2 ampere/sec. What is the EMF developing across the coil?

According to Faraday's Law,

⇒ EMF = L × di/dt

Here, L refers to the Induction and di/dt refers to change of current with respect to time.

⇒ EMF = 5 H × 2 A/s

⇒ EMF = 10 H.A/s = 10 V

Therefore the EMF developed in the coil is 10 V.

Hope it helped !!

Answer 2

Answer:

Combined formula with lens law:

As emf = - L(di/dt)

emf = - ( 5 * (-2) ) V

(-2 as current is in decreasing order.)

Therefore,

emf = 10 V

Here, L is induction

NOTE:-

In general the emf is calculated in the direction of the current.