3.3 Refraction Flashcards
What happens if the angle of incidence is 0degrees?
the wave experiences a change in speed but not a change in direction.
What is refraction?
The bending of a wave (changes direction) when a wave traverses a boundary between two mediums at an angle.
What happens when an incident ray passes from air to glass (less dense to more dense) ?
The ray bends towards the medium.
i>r
What happens when an incident ray passes from glass to air (more dense to less dense) ?
ray bends away from the normal
i<r
What is a lens?
An object designed to refract light rays for a given purpose.
What effect does a converging lens have on parallel rays?
Reflects them to a focus
What is focal length? What is the symbol and unit?
Distance between the centre of the lens and focal point
f
metres (m)
How does changing the curvature effect the focal length of a converging lens?
higher curvature means shorter focal length
lower curvature means longer focal length
What effect does a diverging lens have on parallel rays?
reflects the rays away from a focus.
How does changing the curvature effect the divergence of a diverging lens?
lower curvature means lower divergence
higher curvature means higher divergence
What three things are ray diagrams used to illustrate and determine?
- location
- orientation
- magnitude
What two ways can an image be classified in terms of location?
real- can be formed on a screen (opposite side of lens to the object)
virtual- cannot be formed on a screen (same side of lens as object)
What two ways can an image be classified in terms of orientation?
upright-same as object
inverted-opposite to object
What two ways can an image be classified in terms of magnitude?
enlarged- larger than object
diminished- smaller than object
Where do the two lines go in a ray diagram when looking at images?
- first line goes from top of object to lens in a straight line and then a straight line form that point of lens through the first focal length
- second line goes from top of object through origin
