The potential difference across the terminals of a storage battery not connected in any circuit is observed to be 12 V. When it is connected to an external resistance the potential difference across the terminals is observed to be 11 V while the current in the external resistance is 2 A. What is the internal resistance of the battery?
resistance = voltage drop / current
so 1/2=.5 OHM
To find the internal resistance of the battery, we can use the formula:
V = E - Ir
Where:
V = potential difference across the terminals when connected to an external resistance (11 V)
E = potential difference across the terminals when not connected in any circuit (12 V)
I = current in the external resistance (2 A)
r = internal resistance of the battery (unknown)
First, let's rearrange the formula to solve for r:
r = (E - V) / I
Substituting the given values:
r = (12 V - 11 V) / 2 A
r = 1 V / 2 A
r = 0.5 ohms
Therefore, the internal resistance of the battery is 0.5 ohms.
To find the internal resistance of the battery, we can use the formula for the potential difference across a battery connected to an external resistance:
V = E - Ir
Where:
V is the potential difference across the terminals of the battery (11 V)
E is the electromotive force or potential difference when the battery is not connected to any circuit (12 V)
I is the current flowing through the external resistance (2 A)
r is the internal resistance of the battery (which we need to find)
We can rearrange the equation to solve for r:
r = (E - V) / I
Substituting the given values:
r = (12 V - 11 V) / 2 A
r = 1 V / 2 A
r = 0.5 ohms
So, the internal resistance of the battery is 0.5 ohms.