Induced Electromotive Force Formula

The magnetic field crosses an area formed by a loop, and the flux changes in time, the charges will move in the conductor and that can be associated with a voltage. This is also known as Faraday's law. There is a minus sign refered to as the EMF that is generated oppose the change of magnetic flux. For a single loop, the voltage generated is:

Induced EMF = - Change in the Magnetic flux / change in time

The equation is:

EMF = - ΔΦ /Δt

Where:

EMF: Electromotive force

ΔΦ: Change of the magnetic flux

Δt: change in time

EMF Formula Questions:

1) A magnetic flux changes from 1 T m² to 0.3 T m² in 2 seconds. What is the EMF?

Answer:

From the formula of the EMF,

EMF = - (0.3 Tm² - 1 Tm²)/(2 s) = -(-0.35) T m²/s = 0.35 V

2) A magnetic flux changes from 2 T m² to 10 T m² in 10 seconds. What is the EMF?

Answer:

From the formula of the EMF,

EMF = - (10 Tm² - 2 Tm²)/(1 s) = -(8) T m²/s = -8 V