Refraction Flashcards
Why does refraction occur?
Refraction is the bending of light.
It is caused by light slowing down or speeding up as it changes media.
What are the two refractions in a lens?
The first refraction is when light hits the lens (air to glass). The second refraction is when light leaves the lens (glass to air).
mention speed and direction when explaining
What’s the difference between a lens and mirror?
A mirror is opaque and a lens is transparent. Mirrors create images using reflection and lenses create images using refraction.
What type of lens is thin at the centre?
Concave lens
SALT for an object between F’ and 2F’?
S- larger
A- inverted
L- beyond 2F
T- real
What type of lens always has the same SALT and what is the SALT?
Concave lens.
S- smaller
A- upright
L- between O&F
T- virtual
SALT for an object at F’?
No image
What are the rules of refraction?
1) The incident ray, reflected ray, refraction ray and normal are on the same plane.
2) When light travels from a fast to slow medium, light refracts toward the normal. When it travels from a slow to fast medium, light refracts away from the normal.
SALT for an object beyond 2F’?
S- smaller
A- inverted
L- between F&2F
T- real
SALT for an object between O&F’?
S- larger
A- upright
L- behind lens
T- virtual
SALT for an object at 2F’?
S- same
A- inverted
L- at 2F
T- real
What are the differences between concave and convex lenses?
Convex SALT differ and concave SALT are always the same
Concave are thin at the centre and convex are wide at the centre
Concave has a virtual focus and convex has a real focus
Where is the primary focus(F) in a concave lens?
The same side as the object
In a concave/diverging lens, where do the light rays go after refraction?
The light rays spread apart and look like they came from a virtual focus
Is from a fast to slow medium away from or towards the normal?
Toward the normal
