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Parallel Circuits

• In parallel circuits, each component is connected separately to the positive and negative end of the power supply.
• Ammeter ALWAYS connected in series.
• If you remove one component = hardly affects the others
• Everyday circuits are often a mix of series and parallel circuits
• Potential difference is the same as all components get the full source potential difference: V1 = V2 = V3….
• Current is shared between branches: I total = I1 + I2 + I3….
• In parallel circuits, there are junctions where current splits or re-joins. Total current going into a junction = total current leaving

• Two identical components = same current
• Two resistors in parallel = total resistance is lower than the resistance of the smallest of the two resistors. This is because:
• In parallel = both resistors have same potential difference = the pushing force making the current flow is the same as the source potential difference for each resistor = by adding another loop , current has more directions to flow in = increases total current that can flow around. Using V=IR an increase in current means a decrease in total resistance.

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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