Chapter 28 Flashcards
(102 cards)
Who was the first person to make a systematic study of color?
Newton
By passing a ________beam of sunlight through a _______-_______ glass prism, Newton showed that sunlight is composed of a mixture of…..
narrow; traingular-shaped; all the colors of the rainbow
What does the glass prism do?
The prism cast the sunlight into an elongated patch of colors on a sheet of white paper.
What does the spectrum consist of?
red, orange, yellow, green, blue, violet
What is sunlight an example of?
White light
What is white light?
A combination of all the colors
What happens to objects placed under white light?
White objects appear white and colored objects appear in their individual colors.
What did Newton prove about the colors of the spectrum?
The colors in the spectrum were a property of the the white light itself not the prism.
Is white a color?
No, it is a combination of all colors.
Is black a color?
No, it is the absence of light
When do objects appear balck?
Objects appear black when they absorb light of all visible frequencies.
What is an excellent absorber of light?
Carbon soot and the dull finish of black velvet
Why do highly polished razor blades appear black when stacked upon each other?
Most of the light that gets between the closely spaced edges of the blades gets trapped and is absorbed after being reflected many times.
Do black objects that you CAN SEE absorb all light that falls onto them?
No, bc there is always somereflection at the surface. If not, you wouldn’t be able to see them.
Why are the colors of most objects around you like that?
It is like that due to the way the objects reflect light
The color of an _______ object is the color of the light it reflects
Opaque
What is light reflection similar to?
The way that sound is reflected. It can be made to vibrate, just like we think of atoms and molecules as 3D tuning forls with electrons that behave as tiny oscillators that whirl in orbits around the nuclei. Electrons can be forced temporarily into larger orbits by vibrations of electromagnetic waves (such as light)
Different __________ have different _________ _________ for _________and ___________ ____________.
materials; natural frequencies; absorbing; emitting radiation
At the resonant frequencies where the amplitudes of oscillation are large….
light is absorbed
When frequencies below and above the resonant frequencies…
light is reemitted
If the material is transparent…
the reemitted light passes through it
If the material is opaque…
the light passes back into the medium from which it came, i.e. reflection
What do most materials do when they absorb lightof some frequencies?
They absorb light of some frequencies and reflect the rest
If a material absorbs light of most visible frequencies and reflects red…
the material appears red