Question

In a closed circuit containing a bulb and a cell, the electromotive force (ε) and the terminal voltage (V) is related as. 

(Given I is current and r is internal resistance.)

Options

• V = ε + Ir

• V = ε − Ir

• V = ε ÷ Ir

• V = ε × Ir

Answer 1

V = ε − Ir

Explanation:

The terminal voltage is the voltage across the circuit when it is closed and is lower than the electromotive force (emf) because a portion of the current traverses the cell’s internal circuit.