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Energy Matters


These ugly pylons that blight the landscape carry the cables that bring electricity straight to our homes.
Electricity is `made` in power stations and transmitted all across the country through such cables. The network of cables is called the National Grid.

In this section of Standard Grade Physics you will find out how the electricity is `made` and delivered to our homes.


Now try these revision questions on Energy Matters.

  1. This is an extract from a newspaper report about energy in the modern world. “..... as a global village we need desperately to conserve our fossil fuels. We drive cars that guzzle petrol not thinking that it has a finite supply."
    a) What is meant by fossil fuels?
    b) What is meant that the fuel is finite?

  2. Write down two renewable energy sources and comment on the advantages and disadvantages of them.

  3. Each large wind turbine is capable of generating 200kW . A large coal fired power station generates 2000MW. How many wind turbines would be needed to replace the coal fired power station?

  4. A large dam has 3 x 1010kg stored 200m up a mountain. If the hydro power station is 80% efficient then how much energy could be used from the dam?

  5. Patricia has been asked by Scottish Power to design a block diagram showing the main stages of a thermal power station. Using the words shown below fill in the block diagram STEAM TURBINE, ELECTRIC GENERATOR, BOILER, CONDENSER.

  6. The output voltage of a power station is 25kV. This voltage is stepped up for the power lines to 400kV.
    a) Why is the voltage stepped up?
    b) The number of turns in the primary coil is 4000. How many turns are there in the secondary?
    c) If the current in the primary is 2000A what will be the current in the secondary coil flowing into the pylons?

  7. The resistance per km of pylon wire is 400 If a current of 40A flows along the wires what will be the power loss each km?

  8. How much energy is required to boil 300g of water from a temperature of 25 C. [SPECIFIC HEAT CAPACITY OF WATER = 4200J/kg/ C]

  9. Susan boils the kettle for a cup of tea. She forgets to put the lid on tight and the kettle continues to boil. Sarah estimates that 0.5kg of water has been changed into steam. Calculate the total energy needed to boil away 0.5kg of water into steam from a temperature of 20 C.

  10. A heater rated at 2kW heats up 1kg of water for 3minutes. Calculate the change in the water`s temperature?

  11. Name three ways in which heat loss can be prevented in a house

  12. Write a short note on how a refrigerator works.



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