Lecture 5 Flashcards
define Light
A narrow band of electromagnetic radiation that can be conceptualized as a wave or a stream of photons.
define Photon:
A quantum of visible light (or other form of electromagnetic radiation) demonstrating both particle and wave properties.
for the purpose of this course what is light considered as
a waveform when traveling through space and a photon when hitting something
what is visible light located on in the spectrul
UV and IR
what colour is associated with shorter wavelengths
blue
what colour is associated with longer wavelengths
purple
how does light interact with things
Light can be absorbed, scattered, reflected, absorbed, transmitted, or refracted.
what happens when light is absorbed
Absorbed: Energy (e.g., light) that is taken up and is not transmitted at all.
what happens when light is Scattered:
Energy that is dispersed in an irregular fashion
Scattered: Energy that is dispersed in an irregular fashion.
When light enters the atmosphere, much of it is absorbed or scattered and never makes where
to the perceiver.
what happens when light is Reflected:
Energy that is redirected when it strikes a surface, usually back to its point of origin
aka when you see a red flower, it is actually a flower absorbing all wavelengths except red because red if being reflected back to you
what heppens when light is Transmitted:
Energy that is passed on through a surface (when it is neither reflected nor absorbed by the surface).
what happens when light is Refracted:
Energy that is altered as it passes into another medium
think pencil in water, it looks broken
The human eye is made up of various parts: what are they
- Cornea:
- Aqueous humor
- Pupil:
- Iris:
- Crystalline lens:
- Vitreous humor:
- Retina:
what is the cornea
The transparent “window” into the eyeball.
allows light to enter the eye
what is the pupil
The dark circular opening at the center of the iris in the eye, where light enters the eye.
because it is a narrow opening, this is what causes the image to flip upside down and left to right before hitting retina
what is the iris
The colored part of the eye, a muscular diaphragm, that regulates light entering the eye by expanding and contracting the pupil.
is a muscle; regulates how much light enters the eye through the pupil
what is the crystalline lens
The lens inside the eye, which focuses light onto the back of the eye.
flexible, causes most refraction in the eye, allows light to be focused at right place in eye
what is the vitreous humour
The transparent fluid that fills the large chamber in the posterior part of the eye.
does nothing to light
what is the retina
A light-sensitive membrane in the back of the eye that contains rods and cones. The lens focuses an image on the retina, which then sends signals to the brain through the optic nerve.
where all the ‘magic’ happens
what is the Aqueous humor: (behind the cornea)
The watery fluid in the anterior chamber.
light starts to refract here
Refraction is necessary for what
to focus light rays onto the retina and this is accomplished by the lens.
what is accomodation
The process in which the lens changes its shape, thus altering its refractive power.
Nearby objects require more or less refraction?
more
because light rays from near objects diverge more.