Section 2 Specification

Section 2: Electricity

a) Units

2.1 use the following units: ampere (A), coulomb (C), joule (J), ohm (Ω), second (s), volt (V), watt (W).

b) Mains electricity

2.2 understand and identify the hazards of electricity including frayed cables, long cables, damaged plugs, water around sockets, and pushing metal objects into sockets

2.3 understand the uses of insulation, double insulation, earthing, fuses and circuit breakers in a range of domestic appliances

2.4 understand that a current in a resistor results in the electrical transfer of energy and an increase in temperature, and how this can be used in a variety of domestic contexts

2.5 know and use the relationship:
power = current × voltage
P = I × V
and apply the relationship to the selection of appropriate fuses

2.6 use the relationship between energy transferred, current, voltage and time:
energy transferred = current × voltage × time
E = I × V × t

2.7 understand the difference between mains electricity being alternating current (a.c.) and direct current (d.c.) being supplied by a cell or battery.

c) Energy and potential difference in circuits

2.8 explain why a series or parallel circuit is more appropriate for particular applications, including domestic lighting

2.9 understand that the current in a series circuit depends on the applied voltage and the number and nature of other components

2.10 describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentally

2.11 describe the qualitative effect of changing resistance on the current in a circuit

2.12 describe the qualitative variation of resistance of LDRs with illumination and of thermistors with temperature

2.13 know that lamps and LEDs can be used to indicate the presence of a current in a circuit

2.14 know and use the relationship between voltage, current and resistance:
voltage = current × resistance
V = I × R

2.15 understand that current is the rate of flow of charge

2.16 know and use the relationship between charge, current and time:
charge = current × time
Q = I × t

2.17 know that electric current in solid metallic conductors is a flow of negatively charged electrons

2.18 understand that:

• voltage is the energy transferred per unit charge passed 
• the volt is a joule per coulomb.

d) Electric charge

2.19 identify common materials which are electrical conductors or insulators, including metals and plastics

2.20 describe experiments to investigate how insulating materials can be charged by friction

2.21 explain that positive and negative electrostatic charges are produced on materials by the loss and gain of electrons

2.22 understand that there are forces of attraction between unlike charges and forces of repulsion between like charges

2.23 explain electrostatic phenomena in terms of the movement of electrons

2.24 explain the potential dangers of electrostatic charges, eg when fuelling aircraft and tankers

2.25 explain some uses of electrostatic charges, eg in photocopiers and inkjet printers.