# Learning Exercise

## Ohm's Law Worksheet

#### Exercise

# Ohm's Law Worksheet

## Introduction

An electric circuit is a closed loop around which electric charge flows.

A source of electrical energy (such as a battery) is required to maintain

the flow. An simple electric circuit consists of a battery with its terminals

connected by one or more conducting elements. In the first part of this experiment,

you will attempt to verify Ohm's law for a single element:

*V = IR*

Where *V* is the emf (voltage), *I* is the current, and *R*

is the resistance of the conducting element.The applet for this experiment

is located at:

http://www.shep.net/resources/curricular/physics/java/physengl/ohmslaw.htm.

## Procedure

### Measurements

Before attempting any measurements, you have to choose a measurement range.

Set the maximum voltage to 10 V and the maximum amperage to 300 mA. Use the

buttons to set the resistance to 30 W. Now you

are ready to begin your measurements. Use the voltage buttoms to step the

voltage values from 1 V through 7 V in 1 V steps. For each applied voltage,

record the current in the table below and calculate the ratio V/I.

**Current Measurements for a 30.0 W resistance.**

Voltage, in volts (V) | | | | | | |

Current, in amperes (I) | ||||||

Resistance R = V/I |

Average value of R = _____________.

Next, change the resistance to 60 W and repeat

the process above.

**Current Measurements for a 60 Wresistance.**

Voltage, in volts (V) | | | | | | |

Current, in amperes (I) | ||||||

Resistance R = V/I |

Average value of R = _____________.

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### Questions

1. How do the currents in the two resistances compare for the same applied

voltage? ___________________________________________________

2. What current would you expect in a 90 W

resistance when a 4.00 V potential is applied? ___________________