Q.1
When the National Grid was established, the cables were all carried by pylons. Now, some of the cables of the supergrid have been buried underground. Which of the following is an advantage of buried high voltage cables?
  • Underground cables lose less energy
  • Underground cables are less likely to be damaged or broken in bad weather
  • Underground cables are more expensive to install
  • Underground cables have lower maintenance costs
Q.2
Why is electricity carried by the supergrid at very high voltage?
  • It is a legal requirement
  • That is the voltage that power station generators produce
  • It wastes less energy
  • At lower voltages, it would not have the power to go all over the country
Q.3
Which of the following would be a good stand-by power station?
  • Coal fired power station
  • Pumped storage hydroelectric power station
  • Wind turbines
  • All of the above
Q.4
Which of the following is an advantage of the National Grid?
  • Electricity is available at a standard voltage throughout Britain
  • If a power station breaks down, others can increase output to compensate
  • It makes electricity much cheaper
  • Sudden increased demands in electricity can be met
Q.5
Why are CHP (combined heat and power) stations more efficient than most fossil fuel burning power stations?
  • They use the heat to heat local buildings as well as to generate electricity
  • They are more modern
  • They are a lot smaller
  • They are run by local businesses so they have to be more efficient to make them more profit
Q.6
The National Grid is a system of what?
  • A system of cables
  • A system of cables and transformers
  • A system of cables, transformers and power stations
  • A system of cables, transformers, power stations and consumers
Q.7
Which of the following contains the missing words from the passage in the correct order? ________ transformers are used at power stations to produce the very high ____________ needed to ensure that electricity is transmitted efficiently through the National Grid. Such high voltages are dangerous to use in the home, so _________ transformers are used in substations near to homes to reduce the voltage to safe levels. The voltage of ________ electricity is about 230 V.
  • Step-up, voltages, step-down, household
  • Large, current, small, safe
  • Step-up, current, step-down, safe
  • Step-down, voltages, step-up, factory
Q.8
Where would you find a step-down transformer?
  • Near to the power station
  • In an electricity substation near to the consumers
  • Part way along the power cables of the National Grid
  • In people's homes
Q.9
About seven to eight percent of the electrical energy is lost in the National Grid, mainly as which type of energy?
  • Thermal energy
  • Light energy
  • Sound energy
  • Kinetic energy
Q.10
The electricity generated at power stations is usually at 25,000 V. Which type of transformer is used to change the voltage required by the supergrid?
  • Step-in
  • Step-out
  • Step-up
  • Step-down
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