Light Flashcards
Light is a form of…
energy
Light travels in…
waves
Light doesn’t need …? to move
matter
What is the speed of light?
about 300,000 km/s
The height of the light waves is the…
amplitude
The top of the light wave is called the…
crest
The bottom of the light wave is called the…
trough
The wavelength distance is…
crest to crest, or trough to trough
Short wavelengths have a…
high frequency
Long wavelengths have a…
low frequency
The 7 types of EMS radiation
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
Luminous objects…
produce light
Non-luminous objects…
reflect light
Transmitted light…
passes through transparent objects
Reflected light…
bounces off objects
Objects that absorb light…
take the energy and convert it to heat energy
White light is formed by…
all the colours being combined/reflected off an object
Objects appear black when…
they absorb all the colours of the spectrum
Objects appear certain colours when they…
reflect that colour and absorb all the others
Regular Reflection
Plane (flat) mirrors reflect light in a regular way (at the same angle)
Diffuse Reflection
Most objects reflect irregular because their surface is not perfectly smooth. Light is reflected in all directions.
Lateral inversion…
occurs when looking at a plane mirror and the writing appears backwards
The Law of Reflection
Angle of Incidence = Angle of Reflection/Light is always reflected away at the same angle that is strikes a mirror
Refraction is…
the bending of light
Medium
is a substance through which light travel can travel
Plural of medium
media
Refraction Index
the density of objects can affect the speed that light can travel
MTLA
When entering a More dense medium the light ray bends Towards the normal. When entering a Less dense medium the light ray bends Away from the normal.
Lenses
lenses are shaped so that light passing through them is refracted (bent) in a particular way
Real image
A real image is produced on a screen when all of the rays from a single point on an object strike a single point on the screen/they have a visible focal point where all rays meet
Virtual image
A virtual image is produced when the rays of light that reach our eyes that appear to come from a real object, but there is no object at the apparent source of the light/the focal point is imagined by finding where the rays would meet, if they could.
Convex Lenses
When light passes through a convex lens, the light rays converge
Will light passing through a convex lens make a Real or Virtual image?
a real image bc they converge at a visible focal point
Concave Lenses
When light passes through a concave lens, the light rays diverge
Will light passing through a concave lens make a Real or Virtual image?
Virtual bc there is no visible focal point you can only find the focal point where the rays would meet if they could
Cornea
Clear window, refracts light, helps to focus the light
Pupil
Hole in the iris, which allows light to enter the eye
Iris
Coloured, changes size to control the amount of light entering the eye
Lens
Refracts light to focus image on the retina. Focal length adjusted by ciliary muscles
Retina
Light sensitive cells (rods & cones) which change light energy to nerve impulses.
Optical nerve
Takes messages from the retina to the brain
Sclera
The white, tough outer layer that protects the eye. Choroid: black layer of blood vessels.
Liquid humour
Watery at the front (Aqueous humour), jelly at the back (Vitreas humour), helps to keep eye’s shape and provide medium for light to travel through.
More light is let in when the pupil is…
dilated
Less light is let in when the pupil is…
constricted
Rods and cones are types of…
photoreceptors
Order the visible colours longest to shortest wavelength
Red, Orange, Yellow, Green, Blue, Indigo, Violet
What is frequency?
how many waves per second
What is the period of a wave?
how long it takes a wave to go through it’s full motion
Why do objects appear different underwater?
Because when the light rays hitting the object leave the water they are entering a less dense medium (air) and bend further away from the normal then hitting our eye and our brain perceives the light to have travelled in a straight line
