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Ohm's Law

Figure from experiment 22 from Physics with Vernier


The fundamental relationship among the three important electrical quantities current, voltage, and resistance was discovered by Georg Simon Ohm. The relationship and the unit of electrical resistance were both named for him to commemorate this contribution to physics. One statement of Ohm’s law is that the current through a resistor is proportional to the potential difference, in volts, across the resistor. In this experiment, you will see if Ohm’s law is applicable to several different circuits using a Current Probe and a Differential Voltage Probe.

Current and potential difference, in volts, can be difficult to understand, because they cannot be observed directly. To clarify these terms, some people make the comparison between electrical circuits and water flowing in pipes. Here is a chart of the three electrical units we will study in this experiment.

Electrical Quantity Description Unit Water Analogy
Voltage or Potential Difference A measure of the energy difference per unit charge between two points in a circuit. volt (V) Water pressure
Current A measure of the flow of charge in a circuit. ampere (A) Amount of water flowing
Resistance A measure of how difficult it is for current to flow in a circuit. ohm (*) A measure of how difficult it is for water to flow through a pipe.


  • Determine the mathematical relationship between current, potential difference, and resistance in a simple circuit.
  • Compare the potential vs. current behavior of a resistor to that of a light bulb.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Physics with Vernier »

Physics with Vernier

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5Picket Fence Free Fall
6Ball Toss
7Bungee Jump Accelerations
8AProjectile Motion (Photogates)
8BProjectile Motion (Projectile Launcher)
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10Atwood's Machine
11Newton's Third Law
12Static and Kinetic Friction
13Air Resistance
14Pendulum Periods
15Simple Harmonic Motion
16Energy of a Tossed Ball
17Energy in Simple Harmonic Motion
18AMomentum, Energy and Collisions
18BMomentum, Energy and Collisions
19AImpulse and Momentum
19BImpulse and Momentum
20Centripetal Accelerations on a Turntable
21Accelerations in the Real World
22Ohm's Law
23Series and Parallel Circuits
25The Magnetic Field in a Coil
26The Magnetic Field in a Slinky
27Electrical Energy
28APolarization of Light
28BPolarization of Light (Rotary Motion Sensor)
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30Newton's Law of Cooling
31The Magnetic Field of a Permanent Magnet
32Sound Waves and Beats
33Speed of Sound
34Tones, Vowels and Telephones
35Mathematics of Music

Experiment 22 from Physics with Vernier Lab Book

<i>Physics with Vernier</i> book cover

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