Episode 119: Preparation for EMF and Internal Resistance Topic

This series of activities, from the Institute of Physics, explores electromotive force (emf), internal resistance, voltage, current and charge. They link with a general discussion of energy transfers within electric circuits, involving energy transfer from a chemical battery to electrical work. Each learning episode is a self-sufficient topic.

The episodes in this section are:

Episode 120: Energy transfer in an electric circuit

Episode 121: EMF and Internal Resistance

Episode 122: Using an oscilloscope

Episode 123: Alternating Current

The activities in this topic will enable students to:

1. describe energy changes in an electric circuit

2. define the emf of a cell

3. demonstrate how the load on a cell reduces its terminal voltage

4. solve problems involving terminal voltage, ‘lost volts’, internal resistance and emf

5. measure emf and internal resistance

6. use an oscilloscope to measure constant and varying voltages

7. describe alternating current in terms of r.m.s. and peak values.