Answers to GCSE Mains Electricity
Practice Questions
1.Describe the difference between two core and three core wire
Two core wire contains only live and neutral wires. It is used for double insulated appliances, with a plastic case.
Three core wire contains live, neutral and earth wires. It is used for metal cased appliances.
2. State the colours of the following wires:
Live – carries the alternating potential difference from the supply to the appliance.
Neutral – completes the circuit. The neutral wire is at 0V, or near to 0V.
Earth – is at 0V, a current only flows along the Earth wire if the appliance is faulty.
3. Explain why both the live and neutral wire is needed for an electrical appliance to work.
The live wire brings alternating potential differece from the power source to the appliance. The neutral wire completes the circuit by providing a path for the electricity to return to the power source.
4. State the function of the cable grip in the plug.
Holds the cable in place to prevent the wire being accidently pulled out of the plug.
Absorption and Emission of EM Radiation
JJ Thomson and Plum pudding model
Ernest Rutherford and the Nuclear Model
Niels Bohr changing the Nuclear Model
Discovering the Proton and Neutron
Measuring radiation from radioactivity
Radiation types and properties
Random nature of radioactive decay
Radioactive contamination or irradiation
Hazards of contamination and irradiation
Studies on the effects of radiation on humans
Different half lives of radioactive isotopes
Nuclear Fission Chain Reaction
Writing nuclear fission equations
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