Who came up with the idea of a geocentric model?
Ptolemy
Who came up with the idea of a heliocentric model?
Nicholaus Copernicus
What does geocentric mean?
Earth centred
What does heliocentric mean?
Sun centred
What do luminous objects in space give out?
Visible light
What does visible light travel as?
Waves
What does interface mean?
Boundary
What is refraction?
The change in direction when a light ray moves into a different material
Where does refraction happen?
Between the interface of two materials
What is the normal line?
The line at right angles to the surface of a mirror or lens when a ray of light hits it
What is another name for a converging lens?
A convex lens
What is the focal length of a lens?
This distance between the focus and the lens
How can you find the focal length of a converging lens?
By focusing the image of a distant object onto a piece of paper and measuring the distance between the lens and the paper
What does the eyepiece lens in a refracting telescope do?
Magnify the image created by the objective lens
What does a refractive telescope consist of?
- a tube
- an objective lens
- an eyepiece lens
Why does refraction occur?
Because light travels at different speeds in different materials
What happens when a ray of light enters a denser material?
It slows down and refracts towards the normal
What happens when a ray of light leaves a dense material?
It speeds up and refracts away from the normal
What does the magnification of converging lenses depend on?
- how curved their surfaces are
- how close together they are placed
