Physics Light Test Flashcards
What Philosopher claimed light came out of your eyes, struck the object, and then came back to your eyes
Empedocles
What philosopher claimed light travels in straight lines and reflects from a surface at the same angle at which it hit it.
Euclid
Is light a wave or a particle?
both
Who first calculated how fast light was traveling in 1675 by looking at moons
Roemer
How fast does light travel?
300,000 km/s
Who set up an octagon of mirrors, one far away at the top of a mountain and the octagon at the bottom. The octagon set a light to the mountain and then the light came back. He measured the speed of light.
Michelson
What is a light year? How fast?
how far light can travel in a year
6 trillion miles per year
Only take about ______ minutes for the light from the sun to hit the earth
7-8
The range for Visible Light
400-700 nm
Long wavelength=______ freq
low
Waves that are too long to see (f is too low)
Infrared
Waves that are too short to see (f is too high)
Ultraviolet (UV)
Photons
Particles of light
Transparent
Light passes through
Opaque
Light absorbs or reflects
what colors are included in white?
Red, orange, yellow, green, blue, indigo, violet
What is black?
the absence of light
Light is an _______ color
additive colors
pigments are _____ colors
Subtractive colors
Why is the sky blue?
Energy comes in causing molecules in the atmosphere to vibrate, since they vibrate fast (high frequency) they appear blue
Why are sunsets red?
Why is the sea blue-green?
Every color but blue-green is being absorbed, but blue-green is being reflected
Reflection vs. Refraction
Reflection is when light bounces
Refraction is when light bends due to change in speed
Can reflection & refraction happen at the same time?
yes
Incident ray
The ray of light that comes from the real image (what is being created)
Reflected ray
What bounces off the reflection
Normal ray
The imagery line that is perpendicular to the reflective surface
What is the angle of incidence & reflection?
equal to eachother
What kind of images do we get from mirrors?
virtual
Why do things refract?
the speed changes
When spearfishing, should you aim above or below? Why?
below, because everything appears shallower?
If you wanted to hit something in the water with a laser light? Would you aim, above, below, or right on the object? Why
Right on the object because the light bends at the same speed as the light in the water
What is a Convex lens? Whats another name for it?
The middle is thicker than the edges, converge
Concave
The edges are thicker than the middle, diverge
What is a Convex lens? What’s another name for it?
The middle is thicker than the edges, converge
Principal axis
the line joining the center of the curvature
what kind of image can be projected on a screen?
Real
If you draw a ray diagram with a line on the 1 focal point, what is true of the new image?
it will never focus
If you draw a ray diagram with a line inbtw 1 & 2 focal point, what is true of the new image?
outside 2, real
If you draw a ray diagram with a line on the 2 focal point, what is true of the new image?
Real on 2
If you draw a ray diagram with a line on the outside 2 focal point, what is true of the new image?
inbtw 1&2 real
If you draw a ray diagram with a line on the 2 focal points, what is true of the new image?
Real on 2
Eye is too small
Hyperopia, farsighted, converging lens
Eye is to big
Myopia, nearsighted, diverging lens
What is true of the new image if you draw a ray diagram with a line on the 2 focal point?
Real on 2
How are we able to see blue?
it is absorbing everything but the combination of light that look blue.
What are complementary colors
When you add the two colors together, they make white
Best mirrors are those that are ______
smooth
Plane Mirror
Mirrors without irregularities
Diffuse reflections
If there are irregularities in the surface, the light will bounce around and go in different directions.
Does light speed up or slow down in water?
slow down
Mirages:
the hot molecules are rising and moving. Because they are rising it makes it so that the light from the sky doesn’t go straight down it bends (refraction) and makes it look like water
Focal Length:
distance from the middle of the lens and the focal point
Magnifying glass/lens: creates a ______- image
virtual
What eye condition is from Muscles are worn out so the lens doesn’t move as much (old eye)
presbyopia
