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Current and Circuit Symbols

• Current = flow of electric charge. Electric charge only flows around a complete circuit if there is a potential difference (voltage). Unit of current is ampere, A
• .

• Single, closed loop = current is the same everywhere
• .

• Potential difference (voltage) = driving force that pushes the charge around. Unit is the volt, V.
• Resistance = anything which slows down the flow down. Unit: ohm Ω
• Current flowing through a component depends on the potential difference across it and resistance of component
• Greater the resistance across component = smaller current that flows (for a given potential difference)
• Q=It>
• Charge flow (coulombs, C) = current (amperes, A) X time (seconds, s)
• More charge = larger current
• Learn these circuit symbols:

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

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.

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.

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.

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

1.

2.

3.

4.

1 2 3 4 5 6

“Every accomplishment starts
With the decision to try.” Gail Dever

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