Ferdous Y and Deqa
12th Physics
02/18/2020
Ohm's Law Lab
Introduction:
Ohm’s law states three forms relating to each other. Those forms being voltage, current, and
resistance which states that the current following through a circuit is directly proportional to the
voltage, but is inversely proportional to the resistance. Thus, if the voltage increase it effects the
current to increase, with the resitance staying the same. The purpose of this lab report was to test
the relationship between voltage, resistance, and current in an electric circuit and especially to
see the change that occurred when one of them was changed. The hypothesis that will be tested
in this experiment will be, during the first trial, If the current of the electric circuit increases then
the voltage of the electric circuit decreases. The second one being the second trial if the
resistance increases then the current of the electric circuit would decrease.
Materials:
● A computer
● Website: ​http://phet.colorado.edu/sims/ohms-law/ohms-law_en.html
● Excel worksheet
Procedure:
Trial 1:
First, open this “ ​http://phet.colorado.edu/sims/ohms-law/ohms-law_en.html​” website. Then use
the electric circuit simulator to adjust the voltage slider at different readings (1.5v, 3v, 4.5v,
6v,7.5v, 9v) so that you can record the reading of the current intensity at each reading. Make sure
to put the records into a table that has the voltage and the current labeled on the top. After that
copy that table to the excel and create a scatter plot graph. Lastly, make sure to analyze the
relationship between voltage, current, and resistance.
Trial 2:
Using the same electric circuit simulator, adjust the resistance at different readings (150 ῼ, 300
ῼ, 450 ῼ, 600 ῼ,750 ῼ, 1000 ῼ) then record the current each time the resistance has been
changed. Create a table using the record from the current and resistance. Then move the table
into excel and create a graph using the table.
Observation:
Trial 1 Data Collection:
This experiment was done with the voltage being the independent variable, the current being the
dependent variable and the resistance being the controlled variable.
The Voltage(V)
The current(mA)
Resistance(ῼ)
1.5
2.7
550
3
5.5
550
4.5
8.2
550
6
10.9
550
7.5
13.6
550
9
16.4
550
Trial 2 Data Collection:
This experiment was done with the voltage being the controlled variable, the current being
independent variable and the resistance being the dependent variable.
The Voltage(V)
The current(mA)
Resistance(ῼ)
4.5
30
150
4.5
15
300
4.5
10
450
4.5
7.5
600
4.5
6
750
4.5
4.5
1000
Discussion:
Based on the experimented data, the increase in the voltage resulted in the current to increase. On
the other hand, the increase of the resistance resulted in the current to decrease. The change of
the voltage does not have any effect on the resistance based on the information that was
experimented. The resistance remained constant as the voltage changed. Also, the resistance had
no effect on the voltage especially based on the data that was experimented on. The relationship
between voltage, current, and resistance was that the current flowing through the circuit was
directly proportional to the voltage and inversely proportionally to the resistance. The first graph
explained the relationship between the current and the voltage was that both of them increased at
a similar rate as the voltage increased. However, the second graph showed that as the resistances
increased the current decreased. The experiment that was observed was to state and show the
relationship between the three elements of Ohm’s law. The hypothesis was proven correct based
on the experiment that was done on the collected data. Some limitations that have occurred
during the experiment were not being able to have a successful graph after couple of tries. After
creating the table and it was ready to input a chart it kept showing the two variables (independent
and dependent) on the x-axis and some other random numbers on the y-axis. However, after
trying so hard in different ways it succeded.