Download Yr 9 – Voltage and Current in series circuits

Yr 9 – Voltage and Current in series circuits
Construct the circuit shown, and answer each of the questions below.
Circuit 1 – 3 cells, 1 bulb, all in series
A
B
Q1. Measure the voltage (‘push’) from each cell. Record your results below.
Voltage from Cell 1
Voltage from Cell 2
Voltage from Cell 3
Q2. How much voltage do you predict the cells will have altogether?
I predict the total voltage of the cells will be _____________________ Volts
Q3. Measure the voltage across all the cells together – were you correct?
I measured the total voltage across the cells and it was ________________ Volts
Q4. Complete the sentence below:
To find the total voltage of batteries connected in series we ………………………… the individual voltages.
Q5. How much of the voltage is used up pushing the charges through the bulb? (Hint: measure the
Voltage across the bulb!)
……………………………………………………………………………………......
Q6. You should find that some of the voltage is ‘missing’. What do you think has happened to these ‘lost’
volts? (you may want discuss this in your group if you are not sure).
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
Q7. Measure the current through the circuit on either side of the bulb, at the points labelled A and B and
write down your results below. What do you notice?
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
Construct the next circuit, shown below, and answer each of the questions for this circuit.
Circuit 2 – 3 cells, 2 bulbs, all in series
B
C
A
Q1. Measure the Voltage from each cell, and then across all the cells together. Record your results below.
Voltage from
Cell 1
Voltage from
Cell 2
Voltage from
Cell 3
Total Voltage
Q2. How much voltage is used up pushing the charges through each bulb? Measure the voltages across
each bulb and record your results below.
Voltage across Bulb 1
Voltage across Bulb 2
Q3. How much voltage do you predict there will be across both bulbs together?
I predict the voltage across both bulbs together will be ___________________ Volts
Q4. Measure the voltage across both bulbs together – were you correct?
I measured the voltage across both bulbs together and it was ______________ Volts
Q5. Use an ammeter to measure the current through the circuit at points A, B and C.
Record your results below.
Current at point A
Current at point B
Current at point C
Q6. What do you notice about the current around the circuit? ………………………………………….
…………………………………………………………………………………………………………………
Q7. What do you think will happen to the brightness of the bulbs if you were to add another bulb into the
circuit? What do you think would happen to the current? Explain your answer.
…………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………..