Question

Two resistors $2\Omega$ and $5\Omega$ are connected in series with a $7V$ battery. Find the potential difference across the $5\Omega$ resistor.

• A. $2V$
• B. $7V$
• C. $5V$
• D. $1V$

Answer 1

The correct option is C

$5V$

For series connection, effective resistance in the circuit is given by:
$R=R_1+R_2$
$\therefore$ Total resistance in circuit, $R=2\Omega +5\Omega =7\Omega$

The amount of current through the effective resistance when connected to $7V$ battery:

$I=\frac{V}{R}$ (ohm's law)

$I=\frac{7V}{7\Omega }=1A$

The current through each resistance is same in the series circuit. Hence, potential drop across $5\Omega$ resistor is given by,
$V=1A\times 5\Omega$
$V=5V$