Question

The relationship between terminal potential difference (V), EMF (ε), current (I), and internal resistance (r) is given by:

Options

• \[V = ε + Ir\]

• \[V = ε / Ir\]

• \[V = ε - Ir\]

• \[V = Ir - ε\]

Answer 1

The terminal potential difference equals the EMF minus the potential drop across the internal resistance. Since the potential drop across internal resistance is \[Ir\], the formula is \[V = ε - Ir\]. This equation shows that terminal voltage is always less than EMF when current is being drawn from the cell.