Unit 1 Section 3 E.m.f. and Internal Resistance

Resistance comes from electrons colliding with atoms and losing energy.

In a battery, chemical energy is used to make electrons move.

As they move, they collide with atoms inside the battery - so batteries must have resistance. Called internal resistance.

Load resistance is the total resistance of all the components in the external circuit.

The amount of electrical energy the battery produces and transfers to each coulomb of charge is called its electromotive force or e.m.f. in volts.

e.m.f. = E / Q

e.m.f. = electromotive force in volts (V)

E =

Q =