CH 11 HW
To see his full height, Blinky Bill who is 1.0 meter tall needs a mirror that is at least
0.50 m tall
How does the average speed of light in glass compare with its speed in a vacuum?
0.67 c
A diver shines light up to the surface of a smooth pond at a 10° angle to the normal. Some light passes into the air above, and the part that reflects back into the water makes an angle to the normal of
10°
What is the speed of X-rays in a vacuum?
3x10^8 m/s
The inks used in printing the full-color photos in a common magazine are
A mixture of cyan and yellow inks on a printed page appears
Is the whiteness of clouds due mainly to reflection or to scattering?
It is due mainly to reflection from water drops that are much larger than atoms
How does the speed of light that emerges from a pane of glass compare with the speed of light incident on the glass?
It is the same
Does light travel faster in thin air or in dense air? What does this difference in speed have to do with the duration of daylight?
Light travels faster in thin air. This causes sunlight to refract downward as it enters the atmosphere that is denser at the surface. The bending sunlight keeps the image of the sun above the horizon longer, increasing daylight duration
What is the law of reflection?
The angle of reflection equals the angle of incidence
Electromagnetic waves can travel in
a vacuum and water
The black fur of a black-and-white bunny is due to light
absorption
The reason that a surface appears darker when wet has to do with
absorption of multiply-reflecting light inside the wet region
The greenish blue of water is evidence for the
absorption of red light
Colors seen on TV result from color
addition
Glass is transparent to light of frequencies that
are below its natural frequencies
A beam of light emerges from water into air at an angle bent
away from the normal
The main difference between a radio wave and a sound wave is
basic nature
If you wish to spear a small blue fish with a red laser beam, you should compensate for refraction and aim your laser
below the sighted fish
A red crab crawling very deep in the water where sunlight is very dim appears
black
If molecules in the sky scattered red-orange light instead of blue light, sunsets would be
blue
What color light is transmitted by a piece of blue glass?
blue
Which has the higher frequency?
blue light
Which has the highest frequency?
blue light
Refraction occurs when light passing from one medium to another
changes speed
The white light from the Sun is a
composite of light of all the visible frequencies
When you read from a printed page, you're seeing reflected light that is
diffuse
Object and image for a plane mirror lie
equal distances from the mirror
Different colors of light correspond to different light
frequencies
Waves in the electromagnetic spectrum differ by _______
frequency
The inversion of your image in a plane mirror is actually an inversion of
front and back
A mixture of cyan and yellow inks on a printed page appears
green
If sunlight were green instead of white, the most comfortable color to wear on a hot day would be
green
Light shines on a pane of green glass and a pane of clear glass. The temperature will be higher in the
green glass
Because of refraction, the Sun near sunset appears
higher in the sky
Infrared waves are often called heat waves because they
induce resonance of molecules in the skin that becomes thermal energy
Most of the waves in the electromagnetic spectrum are
invisible
According to the law of reflection, the incident ray, reflected ray, and normal between them
lie in the same plane
If a light signal and a radio signal were emitted simultaneously from the Moon, the first signal to reach Earth would be
light and radio
Relative to ultraviolet waves, the wavelength of infrared waves is
longer
A wave with a long wavelength has a relatively
low frequency
A changing electric field induces a changing
magnetic field
Glass is opaque to light with wave frequencies that
match its natural frequencies
Because of refraction a fish in the water appears
nearer the surface
Electromagnetic waves consist of
oscillating electric and magnetic fields
Complementary colors are two colors that
produce white light when combined
Visible light that shines on a pane of transparent glass
produces a chain of absorptions and re-emissions through the glass
Which have the longest wavelength: light waves, X-rays, or radio waves?
radio waves
Which have the longest wavelengths when traveling in a vacuum?
radio waves
Magenta light is a mixture of
red and blue light
The three colors that comprise the image on a TV screen are
red, blue, and green
Distant snow-covered hills appear yellowish due to the color of the
reflected light that survives scattering
The whiteness of clouds is due mainly to
reflection
A mirage is a result of atmospheric
refraction
When ultraviolet light is incident upon glass, most atoms in the glass
resonate
The sky is blue because air molecules in the sky act as tiny
resonators that scatter blue light
Because of refraction, a person standing waist deep in a swimming pool appears to have
shorter legs
Refracted light that bends away from the normal is light that has _______
sped up
Refraction results from changes in light's
speed
Refraction results from differences in light's
speed
The colors dispersed by a prism are due to different light
speeds inside the prism
Colors seen on the cover of our paper-bound physical science text book result from color
subtraction
Consider light energy that is momentarily absorbed in glass and then reemitted. Relative to the absorbed light, the frequency of the reemitted light is
the same
In looking at yourself in a steamy mirror you wipe just enough moisture away to barely see a full view of your face. If you move back from the mirror you'll see
the same amount of your face
Light travels faster in
thin air
Light changes direction when traveling from air into glass due to changes in light's
velocity
Light refracts when traveling from air into glass due to changes in light's
velocity
Both sound and light can travel in
water
When light is refracted, there is a change in its
wavelength
The complementary color of blue is
yellow
The brightest color emitted by the Sun is
yellow-green