Physics HW2 Ch.27 & 28
Why does the sky normally appear blue?
Air molecules have resonances in the ultraviolet, so they scatter blue light more than red light.
How does incident light that falls on an object affect the motion of electrons in the atoms of the object?
Incident light makes the electrons oscillate. The electrons then emit light or absorb the light and convert it to heat.
What part of the electromagnetic spectrum is most absorbed by water?
Infrared
What accounts for the whiteness of a cloud?
Water droplets of different sizes scatter a variety of light frequencies, resulting in a white cloud.
Clouds are white due to _________.
scattering
The sky is blue due mainly to atmospheric _________.
scattering
What fraction of the light shining straight at a piece of clear glass is reflected from the first surface?
About 4%
What color results when red is subtracted from white light?
Cyan
Why does the color of sunsets vary from day to day?
Different particles in the air each day scatter and absorb different wavelengths of light, thus giving the sky many different colors.
What kinds of molecules will scatter the low frequencies of light?
large molecules
What kinds of molecules scatter high frequencies of light?
small molecules
Light travels a path from one location to another in the least _________.
time
Why does the sky sometimes appear whitish?
Large particles in the atmosphere scatter longer wavelength light that adds to the blue light to create white light.
What is Fermat's principle of least time?
Light takes the quickest path in going from one place to another.
Why is the sunset red?
Only the low-frequency red light penetrates the thick layers of atmosphere when the Sun is low in the sky.
The color of seawater is a result of the subtraction of what color?
Red
Relative to the distance of an object in front of a plane mirror, how far behind the mirror is the image?
The image is the same distance behind the plane mirror as the object is in front of it.
Why is the sky blue when the Sun is overhead?
The molecules in the atmosphere scatter blue light more than any other light, so the sky looks blue.
What happens when light from the Sun interacts with the molecules of the atmosphere?
The molecules scatter the light.
A sunset appears red in color due to _________.
higher frequencies of light scattered away