3.7.3

Resistance

Test yourself

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

1Principles of Science I

1.1Structure & Bonding

1.2Properties of Substances

1.3Cell Structure & Function

1.4Cell Specialisation

1.5Tissue Structure & Function

1.6Working with Waves

1.7Waves in Communication

2Practical Scientific Procedures and Techniques

3Science Investigation Skills

4Principles of Science II

4.1Extracting Elements

4.2Relating Properties to use of Substances

4.3Organic Chemistry

4.4Energy Changes in Industry

4.5The Circulatory System

4.6Ventilation & Gas Exchange

4.7Urinary System

4.8Cell Transport

4.9Thermal Physics

4.10Materials

4.11Fluids

5Contemporary Issues in Science

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