Light And The Eye Flashcards
Angle of incidence
The angle an incoming Ray makes with the normal
Angle of reflection
The angle a reflected Ray makes with the normal
Diffuse reflection
Reflection of light in many directions from an uneven surface, such as a book or a backpack
Incident Ray
Incoming Ray
Law of reflection
i=r or the law stating that light is reflected at the same angle that it is incident
Normal
An imaginary line that is drawn at right angles to a surface that light is incident a
Upon
Plane mirror
A flat mirror
Refraction
The bending of light as it enters or leaves different substances
Refractive index
A measure of how easily light travels through a substance
Regular reflection
Reflection of light from a very smooth surface, such as still water or a mirror; it produces a clear image
Total internal reflection
When light is Completely reflected from the boundary of two substances; it occurs when the angle of incident is great than the critical angle
Critical angle
The angle of incidence of light that produces an angle of refraction of 90 degrees
Conduction
A method of heat transfer in which heat is passed by vibration of particles
Conductor
A substance that allows heat to flow through it
Insulator
A material that doesn’t conduct heat
Concave lens
Lens that curves inwards
Convex lens
A lens that bulges out wards
Cornea
A transparent covering over the iris of the eye; it bends light into the lens
Focal length
The distance from a lens to its focus
Lens
In the eye it is a flexible structure that enables light to be focused on the retina
Another name for long sightedness
Hyperopia
Long sightedness
The inability to focus on close objects because the eyeball is too long
Optic nerve
A nerve that carries an electrical signal from the retina to the brain
Real image
An image formed when Ray’s of light do actually meet
Retina
Nerve tissue at the back of the eye, consisting of cone cells and rod cells; light is converted into an electrical signal here
Short sightedness
The inability to focus on distant objects because the eyeball is too short
Accomodation
The ability of the lens of the eye to change its shape to adjust its focus
Aqueous humour
Lies between the cornea and the lens .
It is a clear, watery fluid produced by the ciliary body to lubricate the lens and cornea
Cornea
Bends light into the lens
Lies in front of the iris
Is clear
Ciliary body
The lens is connected to the ciliary body
Muscles in the ciliary body change the shape of the lens
Conjunctiva
A membrane that covers the sclera
Choroid
Has a rich blood supply and nourishes the retina
Sclera
White of the eye
Cone cells and rod cells are
More concentrated in the fovea centralis - the sharpest vision
Rod cells are located in the retina
Fovea centralis
Responsible for sharp central vision
Eye muscles
Enable the eye to rotate in its socket
Vitreous humour
Clear fluid between the lens and retina
Dilator muscle
Enlarges the Pupil, allowing more light in the eye
Sphincter muscle
Makes the pupil smaller, which stops light entering the eye
Iris
The coloured part of the eye
It contains the dilator muscles and sphincter muscle as part of its structure
Pupil
An opening in the iris that determines the amount of light entering the eye
