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PRACTICAL: Investigating Resistance

• Investigating resistance in series:
• 1. Find four identical resistors

2. Build a circuit (a cell, resistor, ammeter). Note the potential difference of the battery

3. Measure the current using the ammeter. Use R=V/I calculate resistance

4. Add another resistor, in series, to the circuit

5. Measure the current and the potential difference. Calculate the resistance

6. Repeat steps 4 and 5 until all resistors have been added

7. Plot a graph of number of resistors against total resistance

• Investigate resistance in parallel:
• 1. Build the same initial circuit using the same equipment as before.

2. Measure the total current and calculate the resistance

3. Add another resistor in parallel with the first

4. Measure the total current and using the potential difference of battery, calculate the overall resistance.

5. Repeat 3 and 4 until all resistors have been added

6. Plot a graph of number of resistors against total resistance

• In series = adding resistors, increases total resistance as adding resistors decreases total current
• More resistors= larger resistance in series
• In parallel = total current increases, so total resistance increases.
• More resistors = smaller overall 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.

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

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