1. Internal Resistance

2. Batteries and generators add some resistance to a circuit
Batteries and generators add some resistance to a circuit. This resistance
is called internal resistance.
The actual voltage between the terminals of a batter is known as the
terminal voltage.

3. The Terminal Voltage of a Battery
The car battery has an emf of 12.0 V and an internal
resistance of Ω. What is the terminal voltage
when the current drawn from the battery is (a) 10.0 A
and (b) A?
(a)
(b)

4. Practice 2
A new “D” battery has an emf of 1.5 V. When a wire of negligible resistance is connected between the terminals of the battery, a current of 28 A is produced. Find the internal resistance of the battery.

5. Practice 3
A battery has an internal resistance of Ω and an emf of 9.00 V. What is the maximum current that can be drawn from the battery without the terminal voltage dropping below 8.90 V?

6. Practice 4
When a light bulb is connected across the terminals of a battery, the battery delivers 24 W of power to the bulb. A voltage of 11.8 V exists between the terminals of the battery, which has an internal resistance of 0.10Ω. What is the emf of the battery?

7. Lab Materials: Multi-meter, ceramic resistor, battery, wires.
What you are allowed to do: use M-meter as an A-meter and a V-meter. Direct measurement of resistance is not allowed.