# Cells and Circuits

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1. Jun 2, 2015

### Sowon

Power Source at 6.0V

a) Voltage drop across the parallel branch of the circuit: 0.25V
b) Voltage drop across the light bulb connected in parallel: 0.25V
c) Voltage drop across the light bulb connected in series: 0.5V

2) How would you measure the current through the entire circuit: By putting an ammeter in front of the power source.

3.a) Current through the entire circuit: 0.1A
b) Current through the light bulb connected in parallel: 0.05A
c) Current through the light bulb connected in series: 0.1A

Introduction:

1. Compare the values of the current flowing through the light bulbs: As I have thought, the current in parallel circuit is smaller than the series circuit.

2. Compare the values of the current flowing through the series and parallel section of the circuit: The values are lower in parallel circuit and in series circuit the current values are higher.

3. Describe how you could determine the resistance of each light bulbs: (I have no clue)

5. Imagine that you are using cells instead of variable power source. Consider the following changes made to the circuit. What happens to the brightness of the light bulbs? Explain what caused changes in the brightness.
This part is the part that I have no clue on too

a) One more cell is added in series to the circuit:
b) One more cell is added in parallel to the circuit:
c) One more resister is added in series to the circuit:
d) One more resistor is added in parallel to the circuit:

This is the diagram of the circuit (the best I can provide sorry for bad quality):
http://puu.sh/iarE6/7639d4310f.jpg

2. Jun 2, 2015

### SammyS

Staff Emeritus
Post that as an image:

For question 2) When you answer, " By putting an ammeter in front of the power source." Where exactly do you mean? Is that the only possible placement ?

Do you know the resistance of each resistor?

To answer 3 & 4: Do you know Ohm's Law ?

3. Jun 2, 2015

### Sowon

For #2 if you put the ammeter connecting directly with other light bulbs and resistors you'd be able to get the current from power source. Since in a series circuit all the current must be the same therefore I guess in series circuit it doesn't matter but the upper part of the diagram which is a parallel circuit will matter where you place the ammeter.
#3, #4 Yes I know, Ohm's Law which is V = IR but I'm not sure how I can explain it in words... Which is #3. Also, I do not know the resistance of each resistor that's why it's in the question I think.

4. Jun 2, 2015

### SammyS

Staff Emeritus
with what other light bulbs and resistors?

If you mean bulb #1 and the resistor that's between bulb #1 and the power source, that's right. Actually, anywhere from where it's shown in the circuit diagram to just above the switch is fine.