physics test 2

how many colors of ink are used to print full-color pictures?

3 plus black

a person stands 2 meters in front of a plane mirror and sees her image. how far from her does her image appear to be?

4 meters

how does a pigment affect light?

a pigment selectively absorbs some frequencies of light and transmits others

the solar radiation curve is

a plot of suns brightness versus frequency of emission

the main difference between the retina of a human eye and that of a dogs eye is the

absence of cones in a dogs retina

when the frequency of light matches the natural frequency of molecules in a material, light is

absorbed

why are red, green, and blue called the additive primary colors?

adding appropriate amounts of re plus green plus blue lights can produce almost any color of the spectrum

if 3 primary colors of light shine on a white wall and produce a white spot, the primaries must be

additive

why does the sky normally appear blue?

air molecules have resonances in the ultraviolet, so they scatter blue light more than red light

strictly speaking, to say that an apple is red means that it

appears red

glass is transparent to wave frequencies that

are below its natural frequencies

when visible light is incident upon clear glass, atoms in the glass

are forced into vibration

why does your instructor say that every drawing showing what an atom looks like is wrong?

atoms are too tiny to even have the property of appearance

if a light wave is diminished in intensity by absorption of its energy, we say the light is

attenuated

if molecules in the sky scattered orange light instead of blue light, sunsets would be colored

blue

what color light is transmitted by a piece of blue glass?

blue

a banana will appear black when illuminated with

blue light

what are detected by the cones in our eyes?

colors

the sensation of color is seen when light falls on the eyes

cones

stare at a red wall for a few minutes and then gave at a white wall. due to retina fatigue you see

cyan

when something is painted red, what color is most absorbed?

cyan

a red apple will appear black when illuminated with

cyan light

why are metals shiny?

free electrons in metals vibrate when light strikes them, thereby reemitting the light as reflected light

what color of light is most attenuated by magenta-colored paint?

green

what is the fate of the energy in infrared light incident on glass?

infrared light will make atoms vibrate, thus becoming internal energy and a temperature increase

colors are barely seen or not at all in the nighttime because the moonlight

is too dim to activate the retinas cones

what happens to the light when it falls upon a material that has a natural frequency equal to the frequency of the light?

it is absorbed

what happens to light when it falls upon a material that has a natural frequency above or below the frequency of the light?

it is reemitted

green light + ____ light = white light

magenta

what are the subtractive primary colors?

magenta, cyan, and yellow

when red, green, and blue lights shine on a golf ball, the shadows cast are

magenta, cyan, and yellow

which of the following is most directly related to the terms 'resonance' and 'frequency'?

matching

the sky is blue because ai molecules in the sky act as tiny

optical tuning forks that scatter blue light

kids in elementary school get this right: which color go light gets through the red glass?

red

what color of light is transmitted through a piece of red glass?

red

when ultraviolet light is incident upon glass, atoms in the glass

resonate

with all 3 lights are on, we insert an object that casts a shadow. what will be the colors of the shadows, and why?

the 3 shadows will be cyan, yellow, and magenta, because these are the compliments of the 3 primary colors

what is the effect on the color of a cloud when it contains an abundance of large droplets

the clouds become dark

what is resonance?

the enhanced response of an oscillator when a driving frequency matches the oscillators natural frequency

the sound coming from one tuning fork can force another to vibrate. what is the analogous effect for light?

the light emitted by resonant vibrations of an electron around one atom can be absorbed by an electron with the same resonant frequency of vibration in another atom

what are the colors of the shadows cast by an object that is placed under blue and red lights only?

the red light casts a blue shadow and the blue light casts a red shadow, because the space not illuminated by red is illuminated by blue, and vice versa

what occurs when the outer electrons that buzz about the atomic nucleus encounter electromagnetic waves?

they are forced into vibration, absorbing or emitting electromagnetic waves

in what region of the electromagnetic spectrum is the resonant frequency of electrons in glass

ultraviolet

what is the fate of the energy in ultraviolet light that is incident upon glass?

ultraviolet light will be absorbed by the resonant vibration of electrons and turned into internal energy and a temperature increase

why do opaque materials become warmer when light shines on them?

vibrations given by the light to their electrons, atoms, and molecules that absorb the light become internal energy, thus leading to a temperature increase

what is the fate of the energy in visible light that is incident upon clear glass?

visible light will be transmitted by the glass, losing little energy in the process, so the energy remains visible light energy

yellow light + blue light =

white

magenta + yellow + cyan =

white light

if you have 3 primary colored light sources and you turn off the blue, what color will it make?

yellow

to what color of light are our eyes most sensitive?

yellow-green

what is the color of the peak frequency of solar radiation when it is plotted versus wavelength?

yellow-green

your friend says that the reason the distant dark mountains appear blue is because youre looking at the sky between you and the mountains. do you agree?

yes i agree