C: Light and Optical Systems, section 1 and 2: optical devices, reflection, and refraction Flashcards
What was the problem with Pythagoras’ theory about light?
We would be able to see in the dark
What did Euclid discover?
When you shine a beam of light on a flat mirror the angle between the incoming beam and the mirror is equal to the angle of the reflected beam
What did Al-Haytham discover about light?
He said that light bounces off objects and then into the eye
What is white light made of?
Newton discovered that by shining light through a prism it is a combination of different colors
What are the properties of light?
Light travels in straight lines
Light can be reflected
Light can bend
Light is a form of energy
What did Ptolemy discover?
He discovered how light bends when it goes from air to glass
What is the formula for the speed of light?
Speed=distance (km)
————-
time (sec)
What is an optical device?
Any technology that uses light
Who discovered microscopes?
Hans and Zacharias
How do microscopes work?
Light is reflected from a mirror and goes through the specimen and then to the objective and then eye piece
Who discovered telescopes?
Galileo
What are the two types of telescopes?
Reflecting and refracting
Describe refracting telescopes
Refracting telescopes have 2 lenses one on each end of a long tube, the larger lens gathers light and focuses the light to the eyepiece
Describe a reflecting telescope
It uses a large circular mirror that curves inward to gather light. Another mirror that directs it to a an eyepiece
How do binoculars work?
It has an objective lens and two reflective prisms that direct light to the eye
What did Pythagoras believe about light?
He thought light consisted of beams that came from ones eyes
What is a ray diagram?
Ray digrams show how light travels
What does transparent mean?
You can see through it clearly and it has little or no reflection
What does translucent mean?
It allows some light to pass through
What does opaque mean?
Does not allow light to pass through
What does non-luminous mean?
They do not produce light
What does luminous light mean?
It produces light
What is regular reflection?
It is when light hits a smooth surface and reflects in all the same way making a clear reflection.
What is diffuse reflection?
When light hits a rough surface and reflects in all different angles
What makes a good reflector?
A material that is shiny and smooth
What is the incident Ray?
The incoming light
What is the reflecting Ray?
The beam that bounces off a surface
What is a plane mirror?
A flat mirror
What is a normal?
An imaginary line perpendicular to a surface
What is the law of reflection?
The angle of reflection is equal to the angle of incidence
What is a concave mirror?
It has a surface that curves inward
What is a focal point?
Where all the light rays intersect
What does a concave mirror do to the orientation of images?
If the image is between the focal point and the mirror than it is upright
What is a convex mirror?
A mirror with a surface curved outwards
What does a concave mirror do to light rays?
Crosses the light rays at the focal point.
It spreads out light if you are past the focal point, but also flips the image upside down.
What is refraction?
The bending of light as it moves from one medium to another
Why does light refract?
When light goes from one density to the other it changes speed and when entering on an angle it creates a situation much like running into water where you catch one leg in the water before the other, causing your body to turn. The water is more dense than the air so the water slows you down.
What is a lens?
If is a piece of curved glass or other transparent material
What happens when light passes through a concave lens?
The rays diverge (spread out) due to refraction combined with the angle of entry compared to the curved surface. The exit also produces refraction.
What happens when light goes through a convex lens?
They focus into a focal point
What is a real image?
Light can be projected, but they are upside down
