Q.1
What is transferred through the National Grid?
  • Coal
  • Petrol
  • Gas
  • Electricity
Q.2
What voltage is used to transfer electricity through the National Grid?
  • Up to 300,000 V
  • Up to 400,000 V
  • Up to 500,000 V
  • Up to 600,000 V
Q.3
How is such a high voltage produced?
  • By using step-up transformers
  • By using step-down transformers
  • By using a Darlington pair
  • None of the above
Q.4
Why is a high voltage used?
  • It increases the amount of energy wasted in cables
  • It reduces the amount of energy wasted in cables
  • The cables cannot transfer low voltage electricity
  • So they can transfer the electricity at a high current
Q.5
What is the mains voltage in homes in the UK?
  • 120 V
  • 170 V
  • 230 V
  • 270 V
Q.6
How is voltage from the National Grid changed into 230 V for home use?
  • Step-up transformer
  • A thin cable
  • A thick cable
  • Step-down transformer
Q.7
Electricity is sent through the National Grid using which type of electrical current?
  • Alternating current
  • Direct current
  • Alternating and direct current
  • Neither alternating nor direct current
Q.8
What voltage is produced in power stations?
  • 15,000 V
  • 20,000 V
  • 25,000 V
  • 30,000 V
Q.9
Why don't birds get electrocuted when they stand on pylon wires?
  • They do get electrocuted
  • As they are not connected to any grounded point, the electricity will not flow through the bird and will continue through the cables
  • Birds do not conduct electricity
  • None of the above
Q.10
Why does reducing the current and increasing the voltage mean less energy is lost?
  • A high voltage means they can transfer the electricity at a high current, transferring it at a high current means fewer electrons travelling through the cables which reduces the amount of collisions between electrons and the cables, thus wasting less energy as heat
  • A high voltage means they can transfer the electricity at a low current, transferring it at a low current means fewer electrons travelling through the cables which reduces the amount of collisions between electrons and the cables, thus wasting less energy as heat
  • A high voltage means they can transfer the electricity at a low current, transferring it at a low current means more electrons travelling through the cables which reduces the amount of collisions between electrons and the cables, thus wasting less energy as heat
  • A high voltage means they can transfer the electricity at a low current, transferring it at a low current means fewer electrons travelling through the cables which increases the amount of collisions between electrons and the cables, thus wasting less energy as heat
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