Question

explain how the rate of change of flux affects the induced E.M.F. in a conductor

Answer 1

We can understand the generation of E.M.F. in a conductor by understanding the Faraday's Law of Induction and Lenz law.

• Faraday's Law of Induction: An E.M.F. is induced in a conductor when the number of magnetic field lines that pass through the conductor are changing.
• Lenz Law: The direction of induced current in a conductor is such that magnetic field due to the induced current opposes any change in the magnetic flux that induces the current.

Magnetic flux through a conductor is defined as the amount of magnetic field lines passing through that conductor. If the conductor encloses an area A and is placed in a magnetic field then the magnetic flux () through the conductor is given as,

According to the Faraday's law, a change in the magnetic flux with respect to time (t) will result in induced E.M.F. () as,

Now we make use of Lenz law to write,

where the negative sign implies that the current due to this E.M.F. will oppose any change in the magnetic flux.

The above relation now gives the relation between rate of change of flux and the induced E.M.F. in a conductor.