Electromotive Force and Internal Resistance

Electromotive Force (e.m.f) and Internal Resistance

3.3

Electromotive Force (e.m.f) and Internal Resistance

Electromotive force, \(\varepsilon\)

Energy transferred or work done by an electrical source to move one coulomb of charge in a complete circuit.

\(\varepsilon=\dfrac{E}{Q}\), where, \(\varepsilon\) = electromotive force, E = energy transferred / work done, Q = the amount of charge flowing

Internal resistance, r

Resistance caused by electrolyte in the dry cell.

\(\varepsilon > V\)

\(Ir = \varepsilon - V\)

	Formula relating E, V, I, R and r
	\(\varepsilon = V+Ir\) \(\varepsilon = I(R+r)\)