Physics
Electric Circuit Lab
Data Analysis Sheet
Name
Using the data you collected in the lab you can check to see if the work you did in lab was done correctly. If you find you’re
answering no to a lot of these questions, you might want to go back and try them again. The rules of electric circuits are
outlined in this analysis. Include units!
Circuit 1
Q1. Does the voltage across each battery add up to the total voltage across both at once (ie., does V1 + V2 = Vtotal)?
Show your values below. This means that voltages in series add.
Circuit 2
Q2.
Does the voltage across the resistor equal the voltage across the battery?
Record the values here:
Q3.
Why should that be true?
Q4.
Is the current the same on both sides of the resistor? Why should this be true?
Record the values here:
Q5.
Does (current in amps through resistor) x (resistance of resistor in ohms) = voltage of the resistor in volts? Show your
calculations below (include units).
Q6.
How close in % is this calculation to the actual voltage? Show your calculations.
V = I x R is known as Ohm’s Law and works for a resistor.
Circuit 3
Q7.
Does V1 + V2 = VB ?
show values:
Again, voltages in series add (for both resistors and
batteries in series). We’ll call VB the total voltage.
Q8.
Is I1 = I2 = I3 ?
show values:
The current in a series circuit is the same everywhere.
Q9.
Let’s call the current just I (in amps) since they are all the same. (Show calculations below using amps for current,
not milliamps - include units)
Does IR1 = V1 ?
Does IR2 = V2 ?
Gee, Ohm’s law works again!
Q10.
Let’s consider the two resistors as one. Add the value of the two resistors. Then multiply by the current in the
circuit (in amps). Include units.
Does I(R1 +R2 ) = VB ?
Resistors in series add to a total resistance using the following formula:
R total = R1 + R2 + .......... (how ever many you have in series)
and Ohm’s law works for the circuit as a whole, not just for single resistors.
Circuit 4
Q11.
Does V1 = V2 = VB ?
We’ll call this Vtotal.
show values:
Voltages in parallel branches are equal.
Q12.
Does IB- = IB+ ?
show values:
This means the current leaving the battery equals the
current entering the battery. Let’s call it Itotal.
Q13.
Does I1 + I2 = Itotal ?
show values:
Currents in parallel branches add to the total
current entering or leaving the parallel part of
the circuit.
Q14.
Does Ohm’s law still work for each individual resistor? Show your work below (current in amps). Include units.
Does I1 R1 = V1 ?
Does I2 R2 = V2 ?
Q15.
Calculate Rtotal from Ohm’s law for the entire circuit (I in amps): show your work
V total
Rtotal =
=
=
Ohms (Ω).
Itotal
Now try adding the two parallel resistors like this: show your work below
1
R
total
=
1
+
1
R R
1
=
2
R +R
RR
1
1
2
or
R
=
total
2
RR
R +R
1
=
2
1
=
2
Did you get approximately the same value for Rtotal using the two methods?
Resistors in parallel add like this:
1
R
total
=
1
+
1
R R
1
+ .............
2
Ohms