Question

A battery of emf $15$V and internal resistance of $4\Omega$ is connected to a resistor. If the current in the circuit is $2$A and the circuit is closed. Resistance of the resistor and terminal voltage of the battery will be.

• A. $2.5\Omega ,6$V
• B. $3.5\Omega ,6$V
• C. $2.5\Omega ,7$V
• D. $3.5\Omega ,7$V

Answer 1

The correct option is D $3.5\Omega ,7$V

$I=\frac{V}{R}$

$\Rightarrow 2=\frac{15}{4+R}$

$\Rightarrow 8+2R=15$

$2R=7$

$R=3.5\Omega$

Terminal voltage$=15-IV$

$=15-2\times 4$

$=15-8$

$\Delta V=7V$