Transcript P4 - Powerpoint - tonyconnett.com

Physics 4 - Electricity
Assessment details…
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)
Renewable energy sources
Wind
Hydro-electric
Wave
Tidal
Geothermal
Biomass
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
Example
1.
A car engine uses 400J of chemical energy. It produces
250J of heat energy and 30J of sound energy.
Draw a diagram to represent this
energy
energy
energy
energy
2.
3.
How much kinetic energy is produced?
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.
How much energy goes into the motor?
What is the efficiency of the motor?
5.
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.
AQA
Longman 2
Btec
359
194
a.
Describe with examples how electricity can be generated from running water
359
196
b.
Describe with examples how electricity can be generated from sunlight
359
194
c.
360
194-197
d.
Describe with examples how electricity can be generated from wave or tidal
power
Describe advantages and disadvantages with electricity generation by
sunlight, running water and tidal power
360
194-197
e.
Explain why we need a variety of methods to provide a reliable supply when
generating electricity from renewable sources.
282
192, 240
f.
Describe with diagrams how electricity is produced by generators
274
180
g.
274
180
h.
286
242
i.
Choose two appliances in the home and explain the energy changes that
takes place in each
For each appliance above list the useful and non-useful forms of energy
produced.
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)
274
242
j.
Analyse (with examples) the problem of energy wastage when converting it
into other forms for consumer applications
Discuss energy losses in domestic appliances