Question

Derive a relationship between emf, terminal voltage and internal resistance.

Answer 1

Let $E$ be the e.m.f and $V$ be the terminal voltage

The current delivered ( I ) to a load ( R) from a cell with internal resistance (r) can be calculated as:

$I=\frac{E}{R+r}$

And the Potential difference across the load or the Terminal Voltage can be calculated as:

$V=I.R=\frac{ER}{R+r}$