Light Flashcards
How are angles of incidence and reflection measured?
From a line at right angles to the mirror (known as the normal)
What does the angle of incidence equal?
The angle of reflection
What happens when light slows?
It bends towards the normal and the converse
How does the speed change with the amount of refraction?
The greater the refraction the larger the change of speed of light
How can a spectrum be produced in a prism?
The different colours of light travel at different speeds in the glass
What is the difference between red light and violet light in a prism?
-Since red is refracted the least, it slows the least
-Violet is refracted the most because it has been slowed the most
What happens when the angle of incidence in the glass reaches the critical angle?
The angle of refraction in the air becomes 90°
What happens when the angle of incidence in the glass is greater than the critical angle?
Total internal reflection occurs
When does short sight occur?
When the eyes grow slightly too long so that light doesn’t focus on the retina at the back of the eye
What happens with the light rays for the short sighted person?
They focus just in front of the retina, resulting in distant objects appearing blurred
When does long sight occur?
When the eyeball is too short or the lens can’t be made thick enough to focus the light rays on the retina
What do light rays do for a long sighted person?
They focus behind the retina so nearby objects appear blurred
