The National Grid | Improve Tuition | Tutors | Tuition | Tutoring | Tutor

The National Grid


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  • National Grid = giant system of cables and transformers that covers UK and connects power stations to consumers, which are using electricity
  • Transfers electrical power from power stations (supply) to anywhere on the grid where it is needed (demand)
  • Electricity demand changes throughout the day = power stations must produce enough electricity to meet these demands
  • Can predict when most electricity will be used: in the morning, coming home from school/work, when it starts to get dark/cold and popular TV events (sports)
  • There is spare capacity for power stations to cope with the high demand as they work below their max power output
  • Smaller stations can start up in case of emergencies
  • To transmit huge amount of power = need either a high potential difference or a high current
  • But with high current = lose lots of energy as wires heat up and energy is transferred to thermal energy store of surroundings
  • Cheaper to increase the potential difference (400,000V) and keep current low as possible.
  • Increasing potential difference = decreases current = decreases energy lost by heating the wires and surroundings = national grid efficient way of energy transfer.
  • To get potential difference very high it requires transformers, big pylons with huge insulators
  • Transformers step up the potential difference at one end for efficient transmission then bring it back down to a safe level at the other end .
  • Potential difference is increased at STEP UP TRANSFORMER
  • Potential difference is reduced at STEP DOWN TRANSFORMER

How long have you…? (present perfect 4) Exercises


 

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Use the information given to create questions beginning with ‘How long…?’

• It is snowing.

• The weather is shining.

• John and Kate are married.

• My brother has gone on holiday.

• My aunty and uncle live in Canada.

• My sister is a teacher.

• I work at the chemist.

• I’ve known Susan since I was a baby.

• Jonathan is learning to speak to Mandarin.

 

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Fill in the missing gaps in the sentences using the present perfect (=has/have + past participle)

• I have known Kate a long time.

• My brother has been playing the piano he was 11 years old.

• My mum and dad on holiday to America. They

gone since last Sunday.

• I Ben and Emma since primary school.

We to the same primary and secondary school.

• My sister learning to speak French because she
is going to France next month.

 

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Use the appropriate words in the missing gaps.

have you lived       lives      to

has been       works        have known

I have bought       have worked.

• My sister in Spain. She is studying Spanish

with her friend Rosie. I Rosie since I was 5.

• Spencer like with Jamie. They have worked

together for 2 years.

• How long in Australia?

• a new dress for prom.

• He to Thorpe park.

 

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Challenge: Create 4 of your own questions beginning with ‘How long……?’

1.

2.

3.

4.

 

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