# Is a Filament Bulb an Ohmic Resistor?

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Is a Filament Bulb an Ohmic Resistor?

First of all I did some research because to answer the question 'Is A

Filament Bulb an Ohmic Resistor' I needed to know what an ohmic

resistor was.

OHM'S LAW

The current flowing through a metallic conductor is proportional to

the potential difference. This is only true when the temperature is

constant.

If you read the current as you change the potential difference across

a conductor the ratio V/I (volts over amps) is the same if it is

ohmic.

From digitalbrain.com

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An ohmic resistor is a component in which Ohm's law is satisfied.

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OHMIC

VOLTS

[IMAGE] NON OHMIC

AMPS

Preliminary Experiment: Resistance through a wire

=================================================

In this experiment we used a meter stick with wire running down it to

measure the resistance at different distances to decide whether

resistance increases over distance. We changed the voltage or

potential difference 10 times at each length, but in the results table

and graph I have only used the first result from each measurement.

APPARATUS

Meter stick mounted with wire

1 Ammeter

1 Voltmeter

Wire

1 Variable resistor

Crocodile clips

METHOD

1. Attach the ammeter and the voltmeter to the meter stick and

variable resistor.

2. Connect the variable resistor to the power supply and the meter

stick.

3. Plug power supply into the mains and switch on.

4. Check that the voltmeter is showing positive.

Length-cms

Amps-I

Volts-Potential Difference

Resistance-Ohms

0

4.85

0.04

0.008247423

10

2.38

0.46

0.193277311

20

2.08

0.67

0.322115385

30

2.38

1

0.420168067

40

2.2

1.22

0.554545455

50

1.95

1.49

0.764102564

60