A battery of emf 10 V and internal resistance $3 \Omega$ is connected to a resistor. If the current

Question

A battery of emf 10 V and internal resistance $3 \Omega$ is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor and the terminal voltage of the battery?

Professor PC Thomas Classes · Answer

Using $I = \epsilon / (R + r)$, $0.5 = 10 / (R + 3) \implies R = 17 \Omega$. Terminal voltage $V = I 	imes R = 0.5 	imes 17 = 8.5 V$.