1. AQA GCSE Science & Additional Science Physics 1 Topic 5 Hodder Education Revision Lessons Uses and properties of waves Click to continue

2. AQA GCSE Science & Additional Science Physics 1 Topic 5 Overview 1 The different types of electromagnetic radiation travel as waves and move energy from one place to another. They can all travel through a vacuum and do so at the same speed. The waves cover a continuous range of wavelengths called the electromagnetic spectrum. The uses and hazards of the radiation in different parts of the electromagnetic spectrum depend on the wavelength and frequency. Click to continue

3. AQA GCSE Science & Additional Science Physics 1 Topic 5 Overview 2 Sound waves and some mechanical waves are longitudinal, and cannot travel through a vacuum. Current evidence suggests that the universe is expanding and that matter and space expanded violently and rapidly from a very small initial ‘point’, i.e. the universe began with a ‘big bang’. Click to continue What is the electromagnetic spectrum? How do longitudinal waves differ from transverse waves? What is meant by the ‘big bang’?

4. AQA GCSE Science & Additional Science Physics 1 Topic 5 General properties of waves 1 Waves transfer energy. Waves may be either transverse or longitudinal. Electromagnetic waves are transverse, sound waves are longitudinal and mechanical waves may be either transverse or longitudinal. All types of electromagnetic waves travel at the same speed through a vacuum (space). Click to continue

5. AQA GCSE Science & Additional Science Physics 1 Topic 5 General properties of waves 2 Longitudinal waves show areas of compression and rarefaction. Click to continue Waves can be reflected, refracted and diffracted. Waves undergo a change of direction when they are refracted at an interface. What do the terms frequency, wavelength and amplitude mean?

6. AQA GCSE Science & Additional Science Physics 1 Topic 5 General properties of waves 3 All waves obey the wave equation: v = f  λ where v is speed in metres per second, m/s f is frequency in hertz, Hz λ is wavelength in metres, m Click to continue What is the velocity of a wave of frequency 1 kHz and wavelength 50 cm?

7. AQA GCSE Science & Additional Science Physics 1 Topic 5 Electromagnetic spectrum 1 Radio waves, microwaves, infrared and visible light can be used for communication. Click to continue Why aren’t X-rays and gamma rays used for communication?

8. AQA GCSE Science & Additional Science Physics 1 Topic 5 Electromagnetic spectrum 2 Click to continue Name of waveSome usesHazard RadioCommunicationsNone MicrowaveCommunications, cookingHeat and kill body cells Infrared Communications, cooking, thermographs, remote controls Skin burns Visible lightCommunications, laser surgery None unless the source is very bright UltravioletLighting, sunbathingSkin cancer X-raysX-ray photography, CT scansMutate/kill cells, cause cancer Gamma raysTreatment of cancer, numerous industrial applications Kill cells, cause cancer

9. AQA GCSE Science & Additional Science Physics 1 Topic 5 Reflection The normal is a construction line perpendicular to the reflecting surface at the point of incidence. The angle of incidence is equal to the angle of reflection. The image produced in a plane mirror is virtual and upright. Click to continue

10. AQA GCSE Science & Additional Science Physics 1 Topic 5 Sound Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound. The pitch of a sound is determined by its frequency. Echoes are reflections of sounds and can be used to determine the speed of sound. Click to continue Can sound pass through space?

11. AQA GCSE Science & Additional Science Physics 1 Topic 5 The Doppler effect If a wave source is moving relative to an observer there will be a change in the observed wavelength and frequency. This is known as the Doppler effect. Click to continue Explain why the tone you can hear from a racing car changes as it comes towards you and then moves away from you.

12. AQA GCSE Science & Additional Science Physics 1 Topic 5 Red-shift 1 There is an observed increase in the wavelength of light from distant galaxies. The further away the galaxies are, the faster they are moving, and the bigger the observed increase in wavelength. This effect is called the ‘red-shift’. Click to continue

13. AQA GCSE Science & Additional Science Physics 1 Topic 5 Red-shift 2

14. AQA GCSE Science & Additional Science Physics 1 Topic 5 Big bang theory The observed red-shift provides evidence that the universe is expanding and supports the ‘big bang’ theory (that the universe began from a small initial point). Cosmic microwave background radiation (CMBR) is a form of electromagnetic radiation that fills the universe. It comes from radiation that was present shortly after the beginning of the universe. The big bang theory is currently the only theory that can explain the existence of CMBR. Click to continue