Light Target Sheet Flashcards
(26 cards)
How light travels?
Light travels through waves
Know that light travels from a source
Luminous objects/Sun
How shadows are formed?
An object must block light, and they are translucent or opaque
What is the speed of light?
It travels at 300,000km/s
What materials light can travel through?
Translucent and transparent materials
Which materials absorb the most light?
The dark and dull colors
How do we see things?
Light from an object enters directly into our eyes
You see some objects because they are light sources
You see other objects by reflected light
What happens when light hits an object?
Can be transmitted, reflected or absorbed by an objects
What happens when light reflects off different objects?
It goes directly on to your eye
What is a plane mirror?
A plane mirror reflects light regularly so that produces a clear image.
Relationship between the object and the image in a plane mirror
That are the same size
What is the relationship between the incident ray and the reflected ray?
That the angle to the normal is the same size
What is refraction?
Is the change of direction of a ray light as it moves from one material to another
Why refraction happens?
Because there is a change in speed for one material to another
What happens to light when it passes through a glass block?
That the refracted ray it bends towards the normal
Where refraction occurs?
In transparent surfaces
What is a critical angle?
When the angle of refraction is 90* the angle of incidence is called critical angle and the refracted ray runs along the surface/boundary.
What is the total internal reflection?
Is the angle of incidence that is bigger than the critical angle all the light is reflected and no light is refracted ( only occurs when light passes from a more dense to a less dense medium e.g=from glass to air)
What is white light?
White light=is a mixture of many different colors in different frequencies and can be split up into a spectrum of this colors using a prism and light
When light enters the prism you can see each color is refracted by different amounts
This means that the light leaving the prism is spread out into different colors, this process is called DISPERSION
What is the spectrum?
Are seven colors listed in order so their frequency
From lowest to highest frequency
Why some objects appear colored?
When light hits a surface, some of it can be absorbed and some of it reflected.
The light that is reflected is the color of the object and all the other colors are absorbed
How filters can be used to make colored light?
The filter will just let us see the object behind it in black or the color of the filter because just transmits its color
How specialized cells in the eye (CONES) enable us to perceive color?
They only work when the light is bright enough, but not when light is very dim
Are responsible for color vision
There are three types of color vision: blue, green and red
This is why we can’t see colors at night when the light is very dim(Rods)
Rods are responsible for night vision and any let us see in black, white and grey
How images are formed by lenses in our eyes?
Convex lens focus the image on the retina by refracting light, producing an inverted image.
The retina contains cells that are sensitive to light, so they produce electrical impulses when they absorb light the impulses are passed along the optic nerve to the brain, which interprets them
Finally, the brain intercepts the image that right way around
