EM Spectrum Flashcards
What are the two rules of reflection
- Incident angle = reflection angle
- Angles are always measured from the normal
What is the rule of refraction
If entering a denser material it bends towards the normal
If entering a low density material bends away from the normal
What is the incident ray
the angle of the entering ray
What is the reflected ray
the angle of the exiting ray
What is the normal line
Imagery line perpendicular to surface
What is total internal reflection
When light passes from a denser medium into a less dense medium and the angle of incidence is equal to the critical angle
What happens if the angle is equal to critical angle
Light passes along the boundary
What is specular reflection
On a smooth surface all light incident at the same angle exit at the same angle
What is diffuse reflection
Light hitting a rough surface - incident ray is reflected at many angles rathe than one angle
How do coloured filters work
All other colours are absorbed and only a certain colour is able to pass through
What is focal length
The distance between the lens and focal point
What is a focal point
Point where all horizontal rays meet after passing through a lens
What are concave used for
Spreads light waves outwards
What are convex lenses used for
Focuses light inwards
Where is a real image produced
Produces at the opposite side of the lens to the object
Where is a virtual images
Produces an image on the same side of the lens
What are the three characteristics of all EM waves
- Transfer energy
- Transverse
- Travel the same speed in a vacuum
Which wave has the longest wavelength and lowest frequency
Radiowaves
Which wave has the short wavelength and higher frequency
Gamma ray
What are the properties of radiation with higher energy
- Highly ionising
- Harmful to cells and tissues
Properties of radiation with lower energy
- Useful for communications
- Less harmful to humans
What is the wavelength and frequency of the colour red
- Longest wavelength
- Lowest frequency and energy
What is the wavelength and frequency of the colour violet
- Shortest wavelength
- Highest frequency and energy
How do you achieve constant temperature
it needs to radiate the same average power that it absorbs
