Current Electricity

Contents / notes

• Electromotive force (emf), potential difference (p.d.), current, internal resistance of a cell and lost volts.
• Ohm's law, resistivity and conductivity.
• Measurement of resistance.
• Metre bridge.
• Resistance in series and parallel and their combinations.
• Potentiometer method of measuring emf, current and internal resistance of a cell.
• Electrical networks.

Candidate objectives

• Differentiate between emf, potential difference, current and internal resistance of a cell.
• Apply Ohm's law to solve problems.
• Use a metre bridge to calculate resistance.
• Compute effective total resistance for series and parallel arrangements.
• Determine the resistivity and conductivity of a conductor.
• Measure emf, current and internal resistance of a cell using a potentiometer.
• Identify the advantages of a potentiometer.
• Apply Kirchhoff's laws in electrical networks.