P13: EM Waves Flashcards
What are electromagnetic waves?
Electromagnetic waves are transverse waves where the electric and magnetic fields are at 90° too eachother
What are the properties of electromagnetic waves?
- They are all transverse waves
- They all have the same speed of 3 x 10^8
- They can all travel through a vacuum and don’t need a medium to travel through
What is the equation for calculating wave speed?
Wave speed (m/s) = Frequency (Hz) x Wavelength (M)
What is the order of the EM spectrum? (largest wavelength —> shortest wavelength)
Radio waves -> microwaves -> infared -> visible light -> ultraviolet radiation -> x-rays and gamma radiation
What happens when the wavelength of the wave gets shorter?
- More information is carried
- The shorter the range (greater absorption by the atmosphere)
- The less they spread out
What are optical fibres?
Fibres made up of very thin glass
What are some uses of ultraviolet light?
- Sun tans
- Security pens
How are x-rays produced?
When electrons are moving at high speeds with a metal target, x-ray tubes are used to produce x-rays
What is a radiation dose?
A measure of the risk of harm resulting from an exposure of the body to ionising radiation
What are the dangers of x-rays?
X-rays are dangerous as they can cause cell damage and damage too the body if too much exposure
What are the dangers of x-rays?
X-rays are dangerous as they can cause cell damage and damage too the body if too much exposure
