Flashcards
AQA Physics Unit 1 Part 6 - Electromagnetic waves
Cards in this deck (3)
- 16 - Electromagnetic waves6.1 - The electromagnetic spectrum
- Electromagnetic waves are electric and magnetic disturbances that transfer energy from one place to another
- The electronic spectrum is the order of waves from lowest to highest:
radio waves, microwaves, infrared radiation, light, ultraviolet radiation, gamma and x- rays
- All electromagnetic waves travel at a speed at 300 million m/s through space
- to find the speed of waves we use the formula:
v = f x h
- v = wave speed in m/s
f = frequency in Hz
h = wavelength in metres, m
- the wave speed equation is used to calculate the frequency or wavelength of electromagnetic waves - 26.2 - Light , infrared, microwaves and radio waves - white light contains all the colours in the visible spectrum - Infrared radiation happens when the hotter an object is the more infrared radiation it emits - Infrared radiation absorbed into the skin heats up the cells which damages or kills skin cells - Infrared radiation is used for carrying out signals from remote hand sides and inside optical fibres - Microwaves are used to carry satellite TV programmes and mobile phone calls where as radio waves are used for broadcasting TV and radio channels, radio communications and mobile phone signals - Different types of electromagnetic radiation are hazardous in different ways - Micro and radio waves cause internal heating where as infrared radiation causes skin burns6.3 - Communications
- Radio waves of different frequencies are used for different purposes as the wavelength (and therefore frequency) of waves affects how far they go, how much they spread and the amount of information they can carry
- Microwaves are used for satellite TV signals
- Further research is needed to evaluate whether or not mobile phones are safe to use
- optical fibres are very thin transparent fibres that are used to transmit signals by light and infrared radiation - 36.4 - the expanding universe - Doppler effect is the change in the observed wavelength of waves because of the motion of the source of the waves. - Christian Doppler in 1842 demonstrated the effect using sound waves by having an open railway carriage filled with trumpeters. People listened to the pitch as they sped past. - Red shift of a distant galaxy is the shift to longer wavelengths of the light from it because the galaxy is far from us - Blue shift is if the star or galaxy is moving towards us. - the faster a star or galaxy is moving, the bigger the shift is - All distant galaxies show red shift. The further away the galaxy is from us, the greater the red shift. - The distant galaxies are moving away from us as the universe is expanding - Edwin hubble discovered in 1929 that light from distant galaxies is red shifted and also said the further the galaxy the bigger the red shift6.5 - The Big bang
- The universe started with the Big Bang, a massive explosion from a very small point
- The universe has been expanding ever since the big bang
- Cosmic microwave background radiation is electromagnetic radiation caused after the big bang.
- CMBR only explained by the big bang theory
Information
- Description
- GCSE Physics Flashcards on AQA Physics Unit 1 Part 6 - Electromagnetic waves, created by azini on 11/06/2015.
- Created by
- azini
- Views
- 2
- Rating