visible light Flashcards
what is luminous?
an object that gives off light or glows in dark
what is illuminated?
lit up
what is visible light?
- an object that comes from a luminous source
- can be observed by the naked eye
what is radiation?
the process where light moves away from its origin.
how is light transferred?
by radiation.
what happens when lights are switched on?
room becomes illuminated because bulb radiates in all directions.
why cant you see around a corner?
light travels in straight lines
what is a ray diagram?
a simplified way to show how light is radiated from a luminous object
what is a pinhole camera?
- a pinhole camera illustrates that light travels in straight lines
- forms an upside down image of a luminous object on a screen
what is the speed of light?
aproximateley 300 000 km per second
what is the distance from the earth to sun?
150 million km
what is the formula for distance?
time (seconds) x speed (km)
what is the formula for time?
distance (km) divided by **speed **(km/s)
what is the formula for speed?
distance (km) divided by time (seconds)
what is white light?
the combination of all the different colours of light
what is a spectrum of visible light?
the full collection of coulors that make up white light
what is light called?
a wave
what is a wave?
a pattern created by the repeated up and down or side to side movement of a medium which flows through it.
what is a wavelength?
the length of one wave pattern
what is frequency?
the number of waves that move past a certain point in one second
what is white light made up of?
violet, indigo, blue, green, yellow, orange and red
which colour has the shortest wave length?
violet
which colour has the longest wave length and shortest frequency?
red
what is light refraction?
the ability of a wave to change direction or bend when it passes from one medium to the other
what happens when light shines on triangular prism?
each colour has own angle thus splitting white light refracted + dispersed into seven colours
what is an opaque substance?
object that doesnt allow light to travel through it
what happens to opaque objects?
- light = absorbed or reflected
- absorbed: light cannot travel further once reached
- black objects absorb light
where do shadows form?
the area behind opaque objects that recieve no light
what are transparent substances?
objects where light is able to travel through the object
it can be absorbed or reflected
explain how we see colour
if you have a coloured object, the other colours of the spectrum besides the colour of object will be absorbed and the colour of the object will be reflected
if all colour = absorbed, object = black
if all colour= reflected, object = white
explain how you see yourself in the mirror
- light from light source reflects on you
- this light shines on mirror
- when light is reflected it always changes direction
- light reflects back to your eye
- your brain reads that light ray traveled length of the two light rays together
- the brain forms image a distance away
what is the normal?
imaginary line on reflective surface that forms 90 degree angle on surface
what is an incident ray?
light that travels through the reflective surface
what is the reflected ray?
the light that is reflected from the the reflected surface
what is the angle of incidence?
angle measured from the normal to incidence ray.
what is the angle of reflection?
angle measured from the normal to reflected ray.
if surface = rough then reflection = scattered.
draw a ray diagram
draw refraction of light through a triangular prism
draw refraction of light through convex lens
