Answer:
Explanation:
Here we want to find the external resistance of the circuit.
First of all, the terminal voltage of a battery is given by:
where
is the emf
I is the current
r is the internal resistance
According to Ohm's law, when the battery is connected to the external resistance, the voltage on the battery is equal to the voltage drop on the resistor, which is:
where
R is the resistance of the external resistor
Combining the two equations,
Here we have:
is the emf of this battery
is the internal resistance
I = 2 A is the current in the circuit
Solving for R, we find: