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?


The diagram is given as:



Given: Electromotive force (E) of battery = 10 volt.


Internal Resistance r of the battery = 3 Ω


Current in the Circuit (I) = 0.5 A


Let the resistance of the required resistor is R Ω


Let the Terminal voltage of the register be V.


As per Ω ’s law,





R + r = 20 Ω


r = 3Ω


Resistance of Resistor is 17 Ω.


Also, as per Ohm’s law,


V = IR


V = 0.5A × 17Ω =


V = 8.5V


Terminal voltage of the register is 8.5V.


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