the national grid

Question 1

what is the national grid?

Answer 1

a system of cables and transformers linking power stations to consumers

Question 2

what does the national grid transfer?

Answer 2

electrical power from power stations to consumers

Question 3

step-up transformers

Answer 3

• increase the potential difference to 400,000V
• decrease current
• so it is efficient
• a high current would means you lost lots of energy as wires would heat up so energy transferred to thermal energy, therefore a high voltage is used instead

Question 4

step-down transformers

Answer 4

• decrease the potential difference
• increase current
• so it is safe for domestic use

Question 5

why is the national grid efficient?

Answer 5

• very low current means that very little energy is lost by heating to the surroundings
• very high voltage means high amounts of electricity can be transferred at once so cost effective