2.2.1

Resistance

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Resistance

Resistance is a measure of how difficult it is for current to flow through a component.

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Charge flow

  • When charge flows in an electric circuit, the size of the current is affected by two things:
    1. The resistance: If the resistance is increased, the current will decrease.
    2. The potential difference: If the potential difference is increased the current will increase.
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Units - Ohms

  • Resistance is measured in ohms, Ω.

Measuring Resistance

We calculate the resistance using R = V/I. We calculate potential difference using a voltmeter and current using an ammeter at the same time.

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Potential difference across a component

  • To measure the resistance of a component (e.g. lamp or resistor), measure the potential difference across the component.
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Current through a component

  • Use an ammeter to measure the current flowing through a component.
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Resistance

  • The longer the wire, the higher the resistance.

Jump to other topics

1Energy

2Electricity

3Particle Model of Matter

4Atoms & Radiation

5Forces

5.1Basics of Motion

5.2Forces

5.3Effects of Forces

5.4Pressure

6Waves

7Magnetism

8Astrophysics

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