Question

The terminal voltage across a battery of emf $E$ can be

• A. $0$
• B. $>E$
• C. $<E$
• D. All of above

Answer 1

The correct option is C $<E$

The voltage output of a device is measured across its terminals and, thus, is called its terminal voltage $V$. Terminal voltage is given by

$V=E-Ir$

where, $E$ and $r$ are the emf and internal resistance of cell, $I$ is the current through the circuit.

The smaller the internal resistance r, larger the current and smaller the terminal voltage and it is likewise true that the larger the internal resistance, the smaller the terminal voltage. Hence, $V$ less than $E$.