Answer :
Final answer:
The internal resistance of a 6 V battery delivering a current of 1.2 A to a 4.5 Ω resistor is calculated to be 0.5 Ω, by using the open-circuit voltage and applying Ohm's Law.
Explanation:
To find the internal resistance of a battery when it is delivering current to a load, you first need to know the battery's open-circuit voltage (also known as electromotive force or emf) and the voltage across its terminals when the current is flowing.
The open-circuit voltage is given as 6 V, and we can calculate the voltage across the terminals using Ohm's Law, which states V = IR, where V is the voltage, I is the current, and R is the resistance.
When the current of 1.2 A flows through the external resistance of 4.5 Ω, the voltage across it would be 1.2 A * 4.5 Ω = 5.4 V. This means the internal voltage drop within the battery is 6 V (the emf) minus 5.4 V (the voltage across the external load), which equals 0.6 V.
The internal resistance can then be found using the formula for the voltage drop, which is V = IR, rearranged as R = V/I, where R is the internal resistance, V is the internal voltage drop, and I is the current.
Substituting the known values, R = 0.6 V / 1.2 A, which gives an internal resistance of 0.5 Ω.
