Question

In a closed circuit drawing current from cell, the emf of a cell is always

• A. Less than potential difference
• B. More than potential difference
• C. Half of the potential difference
• D. Double of the potential difference

Answer 1

The correct option is A Less than potential difference

The terminal voltage is always less than the cell voltage and depends on external load.Let $R_L$ and $R_{int}$ denote the external load resistance and internal resistances respectively and V be the cell voltage,the terminal voltage is then the terminal voltage is given by,
$V_T=V-I{R}_{int}=V-\frac{V}{R_L+R_{int}}{R}_{int}<V$
Thus,
The terminal voltage is always less than the cell voltage.
P.S. Terminal voltage is maximum and equal to cell voltage in case $R_L$ approaches infinity (Open circuit).