1. Physics 4 - Electricity Assessment details…

2. Generating Electricity 2…. Copy the following diagram… Copy the following notes… Electricity flows in the wire when the magnet is moving The faster the magnet moves the greater the current If the magnet moves in the opposite direction, the current flows in the opposite direction When the magnet is stationary no current flows Current flows when the wires ‘Cut’ the magnetic field lines More turns = more current..! (Demo wire / magnet / galvo)

3. Renewable energy sources Wind Tidal Hydro-electric Geothermal Biomass Wave

4. The National Grid Notes… Power station generates electricity at about 30 000V A transformer increases the voltage to about 400 000V Pylons carry the electricity around the country The electricity is carried at high voltage to reduce the amount of heat generated in the wires At high voltage the current is reduced – with a high current lots of energy is lost as heat A transformer then reduces the voltage to a safe level (230V) for use in our homes

5. Example A car engine uses 400J of chemical energy. It produces 250J of heat energy and 30J of sound energy. 1.Draw a diagram to represent this 2.How much kinetic energy is produced? 3.How efficient is the car engine? 4.An electric motor produces 95 J of kinetic energy, 10 J of heat energy and 5 Joules of sound energy, draw a diagram to represent this. 5.How much energy goes into the motor? 6.What is the efficiency of the motor? energy

6. Scenario – You are supplying electricity to a mountainous village. There is a fast running river close, but it does dry up in the summer. The coast is about 50km away and the weather is sunny most of the time. The village needs a reliable electricity supply 24 hours a day. You have design a electricity supply system for the village. You must also explain why electricity supplied from power stations a long way away is subject to energy losses in the wires. AQALongman 2Btec 359194 a.Describe with examples how electricity can be generated from running water 359196 b.Describe with examples how electricity can be generated from sunlight 359194 c.Describe with examples how electricity can be generated from wave or tidal power 360194-197 d.Describe advantages and disadvantages with electricity generation by sunlight, running water and tidal power 360194-197 e.Explain why we need a variety of methods to provide a reliable supply when generating electricity from renewable sources. 282192, 240 f.Describe with diagrams how electricity is produced by generators 274180 g.Choose two appliances in the home and explain the energy changes that takes place in each 274180 h.For each appliance above list the useful and non-useful forms of energy produced. 286242 i.Analyse the problem (with examples) of energy losses in power lines when transmitting electricity Discuss why electricity is transmitted at such a high voltage (~400 000V) 274242 j.Analyse (with examples) the problem of energy wastage when converting it into other forms for consumer applications Discuss energy losses in domestic appliances