Question

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

Answer 1

It is given that the battery has an emf of 10V, the internal resistance of the battery

is 3Ω and the current in the circuit is 0⋅5A.

The equation for the current is,

I= E R+r

Substitute the value of E, I and r in the above equation,

0⋅5= 10 R+3 R+3=20 R=17Ω

Thus, the value of the resistance of the resistor is 17Ω

The equation for the terminal voltage is,

V=IR

Substitute the value of I and R in the above equation.

V=0⋅5×17 V=8⋅5 V

The value of terminal voltage of battery when the circuit is closed is 8⋅5V.