Question

A battery of emf 10 V and internal resistance 3 W is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?

Answer 1

$E=V+IR$,

$R=E/I-V=17\Omega$

Again using $E=V+Ir$, we get

$V=E-Ir=10-0.5\times 3$

$=10-1.5=8.5V$.