Answer :
Final answer:
The internal resistance of the automotive battery can be calculated using Ohm's Law and the given values for emf, terminal voltage, and current, resulting in an internal resistance of 0.03 ohms.
Explanation:
The emf (E) is the maximum potential difference of the battery, whereas the terminal voltage (V) is the potential difference across the terminals when the battery is connected to a load or being charged. The difference between the emf and the terminal voltage arises due to the internal resistance (r) of the battery itself.
The internal resistance can be calculated using Ohm's Law combined with the concept of emf, which is expressed by the following equation:
E = V + Ir
Where:
- E is the emf of the battery (12.0 V)
- V is the terminal voltage (11.4 V)
- I is the current flowing through the battery (20.0 A)
- r is the internal resistance
To find the internal resistance, we rearrange the equation to solve for r:
r = (E - V) / I
Plugging in the given values:
r = (12.0 V - 11.4 V) / 20.0 A
r = 0.6 V / 20.0 A
r = 0.03 Ω
The internal resistance of the battery is 0.03 ohms (or 30 milliohms).
