6.4.3

Infrared, Microwave & Radio Waves

Test yourself

Infrared Radiation

Infrared (or infra-red) radiation is one type of wave on the electromagnetic spectrum.

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Uses

  • Infra-red radiation is used in TV controls.
  • Infra-red can also be used for security purposes, such as in intruder alarms by detecting body heat.
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Risks

  • Infra-red radiation can cause serious skin burns if emitted from high-intensity sources.
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Explanation

  • The frequency is high enough to excite particles in food. This increases their temperature.
  • Infra-red cameras can detect a range of frequencies. These frequencies can be shown in different colours to depict images.

Microwaves

Microwaves are the 6th type of wave in the electromagnetic spectrum.

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Uses

  • Microwaves are used for the purpose of satellite communications (transmitting signals between stations on Earth and satellites).
  • Microwaves are also used to transmit signal from a nearby phone mast (transmitter) to a mobile phone.
  • Microwaves are absorbed by water, heating up the water in the process. This makes microwaves useful for cooking food because food contains lots of water.
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Risks

  • Because humans are largely made up of water, exposure to microwaves could have a harmful effect.
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Safety

  • We should always reduce any exposure to microwaves.
  • As with X-rays, always have some sort of shielding between the source of microwaves and living tissue.
  • An example of this is the protective shielding on microwave ovens.
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Explanation

  • Microwaves have a high enough frequency to penetrate the Earth’s atmosphere and to reach satellites.
  • Microwaves travel in straight lines through the atmosphere. This makes them good for transmitting (sending) signals.

Radio Waves

Radio waves are used for radio and TV communications.

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Uses

  • Radio waves are used for radio and TV communications.
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Risks

  • At high intensities, radio waves can cause internal heating of living tissue with potentially harmful effects.
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Explanation

  • Because radio waves have long wavelengths, they can be transmitted (sent) around the Earth’s surface and around buildings without interference.

Jump to other topics

1Energy

1.1Energy Changes

1.1.1Energy Stores

1.1.2Calculating Changes in Energy

1.1.3Changes in Kinetic Energy - Calculations

1.1.4Changes in GPE - Calculations

1.1.5Changes in EPE - Calculations

1.1.6Energy Transfers

1.1.7Mechanical Work Done

1.1.8Mechanical Work - Calculations

1.1.9Electrical Work Done

1.1.10Electrical Work Done- Calculations

1.2Energy Losses & Efficiency

1.2.1Energy Losses & Efficiency

1.2.2Energy Losses & Efficiency 2

1.2.3Efficiency - Calculations

1.2.4Grade 9 - Energy & Efficiency

1.3Energy Resources

1.3.1Fossil Fuels & Geothermal Energy

1.3.2Wind & Water Energy Sources

1.3.3Nuclear & Solar Energy

1.3.4Sustainability

1.3.5Renewable Energy

1.3.6End of Topic Test - Energy

1.3.7Exam-Style Questions - Energy

2Electricity

2.1Electric Charge

2.1.1Circuit Diagrams & Components

2.1.2Current

2.1.3Current - Calculations

2.1.4Conductors

2.1.5Potential Difference

2.1.6Voltage - Calculations

2.2Resistance & Electrical Work

2.2.1Resistance

2.2.2Diodes, LDRs & Thermistors

2.2.3Electrical Work

2.2.4Ohm's Law

2.2.5Resistance and Ohms Law - Calculations

2.2.6Electrical Work - Calculations

2.3Electric Circuits

2.3.1Series Circuits

2.3.2Series Circuits 2

2.3.3Series Circuits - Calculations

2.3.4Parallel Circuits

2.3.5Parallel Circuits 2

2.3.6Parallel Circuits - Calculations

2.3.7Grade 9 - Circuits

2.3.8Exam-Style Questions - Electricity

2.4Electricity in Homes

2.4.1Domestic Uses

2.4.2Domestic Uses 2

2.4.3Domestic Uses - Calculations

2.4.4Electrical Safety

2.4.5Electrical Safety 2

2.4.6End of Topic Test - Electricity

2.5Static Electricity

2.5.1Static Electricity

2.5.2Static Electricity 2

3Particle Model of Matter

3.1States of Matter

3.1.1Atomic Structure

3.1.2Atomic Structure 2

3.1.3Density

3.1.4Density - Calculations

3.1.5Changes of State

3.1.6Exam-Style Questions - Density

3.2Heat

3.2.1Internal Energy

3.2.2Heat Capacities

3.2.3Internal Energy - Calculations

3.2.4Latent Heat

3.2.5Latent Heat - Calculations

3.2.6Latent Heat Experiments

3.3Particle Motion in Gases

3.3.1Particle Motion in Gases

3.3.2Particle Motion in Gases 2

3.3.3End of Topic Test - Particle Model of Matter

3.3.4Grade 9 - Particle Model of Matter

3.3.5Exam-Style Questions - Specific Heat Capacity

4Atoms & Radiation

4.1Atoms

4.1.1Atomic Model

4.1.2Atomic Model 2

4.1.3Atoms & Ions

4.1.4Isotopes

4.1.5Exam-Style Questions - Atomic Structure

4.2Radiation

4.2.1Radioactive Decay

4.2.2Radioactive Decay 2

4.2.3Types of Radioactive Emission

4.2.4Fission & Fusion

4.2.5Radioactive Decay Equations

4.2.6Radio. decay equations - Calculations

4.2.7Half Lives & Ionising Radiation

4.2.8Half Life - Calculations

4.2.9Uses & Dangers of Radiation

4.2.10Uses & Dangers of Radiation 2

4.2.11End of Topic Test - Atoms & Radiation

4.2.12Grade 9 - Radiation

4.2.13Exam-Style Questions - Radioactive Decay

5Forces

5.1Basics of Motion

5.1.1Basics of Motion

5.1.2Basics of Motion 2

5.1.3Basics of Motion 3

5.1.4Distance- & Speed-Time Graphs

5.1.5Average Speed - Calculations

5.1.6Acceleration - Calculations

5.1.7Uniform Acceleration - Calculations

5.1.8Grade 9 - Motion

5.1.9Exam-Style Questions - Motion

5.2Forces

5.2.1Gravity

5.2.2Gravity - Calculations

5.2.3Resultant Forces

5.2.4Newton Second Law - Calculations

5.2.5Force Diagrams

5.2.6Free Body Diagrams - Calculations

5.2.7Stretching a Spring

5.2.8Hooke's Law

5.2.9Hooke's Law - Calculations

5.2.10Elastic Potential Energy

5.2.11Elastic Potential - Calculations

5.2.12Exam-Style Questions - Elastic Potential Energy

5.3Effects of Forces

5.3.1Acceleration

5.3.2Acceleration 2

5.3.3Momentum

5.3.4Change in Momentum - Calculations

5.3.5Momentum - Calculations

5.3.6Moments

5.3.7Moments - Calculations

5.3.8Circular Motion

5.3.9Levers & Gears

5.3.10Stopping Distance

5.3.11Decelerations

5.3.12Stopping Distance - Calculations

5.4Pressure

5.4.1Pressure

5.4.2Pressure - Calculations

5.4.3Liquid Pressure - Calculations

5.4.4Pressure Changes

5.4.5End of Topic Test - Forces

5.4.6Exam-Style Questions - Pressure

6Waves

6.1Wave Basics

6.1.1Basics & Formula

6.1.2Wave Speed - Calculations

6.1.3Describing Waves

6.1.4Wave Frequency - Calculations

6.1.5Transverse & Longitudinal Waves

6.1.6Required Practical - Ripple Tank

6.2Waves at a Boundary

6.2.1Waves at a Boundary

6.2.2Waves at a Boundary 2

6.3Sound Waves

6.3.1Sound Waves

6.3.2Sound Waves 2

6.3.3Uses of Sound Waves

6.3.4Sound Waves - Calculations

6.3.5End of Topic Test - Introduction to Waves

6.3.6Exam-Style Questions - Wave Speed

6.4Electromagnetic Waves

6.4.1Properties

6.4.2Gamma, X-Ray & UV Light

6.4.3Infrared, Microwave & Radio Waves

6.4.4Properties 2

6.4.5Visible Light

6.4.6Visible Light 2

6.4.7Grade 9 - Waves

6.5Lenses

6.5.1Lenses

6.5.2Lenses - Calculations

6.5.3Images & Ray Diagrams

6.6Heat & Radiation

6.6.1Infrared Radiation

6.6.2Temperature

6.6.3Greenhouse Effect

6.6.4End of Topic Test - EM Waves, Lenses & Heat

6.6.5Exam-Style Questions - EM Radiation

7Magnetism

7.1Magnetism Basics

7.1.1Magnetic Materials

7.1.2Magnetic Fields

7.2Electromagnetism

7.2.1Electromagnetism

7.2.2Electromagnetism 2

7.2.3Motor Effect

7.2.4Magnetic Flux - Calculations

7.2.5Motors

7.2.6Induced Potential

7.2.7Induced Potential 2

7.2.8Generator Effect

7.2.9Generator Effect 2

7.3Transformers

7.3.1Transformers

7.3.2Transformers 2

7.3.3Transformers 3

7.3.4Transformers - Calculations

7.3.5Transformers 2 - Calculations

7.3.6End of Topic Test - Magnetism

7.3.7Grade 9 - Transformers

7.3.8Exam-Style Questions - Magnetic Fields

8Astrophysics

8.1Astrophysics

8.1.1The Solar System

8.1.2The Solar System - Calculations

8.1.3Orbits

8.1.4Orbits HyperLearning

8.1.5Life Cycle of a Star

8.1.6The Universe

8.1.7End of Topic Test - Astrophysics

8.1.8Exam-Style Questions - Astrophysics

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Gamma, X-Ray & UV Light

Properties 2