PSCI Chapter 12 Test Questions
and Answers All Correct
What does an object's index of refraction indicate? - Answer-it indicates how much light
will slow down in the material compared to its speed in a vacuum
What happens to white light when it passes through a prism? - Answer-the white light
get refracted at different amounts because of its wavelength and get separated into a
rainbow
Is the lens of your eye, your finger-nail, your skin, and your tooth opaque, translucent, or
transparent? Explain. - Answer-lens is transparent because light passes through without
scattering.
Fingernails and skin are translucent because light passes through them but you cannot
see through them.
Teeth are opaque because light doesn't pass through them.
A light ray strikes a mirror at an angle of 42° from the surface of the mirror. What angle
does the ray make with normal? - Answer-48°
A ray of light hits a mirror at 27° from the normal. What is the angle between the
reflected ray and the normal? - Answer-27°
Why does a white fence appear white? - Answer-White fences reflect all colors. Your
eye sees three colors and all three get activated. The brain interprets this as white light
What color would be seen if equal amounts of red light and green light were mixed? -
Answer-yellow
Compare & contrast the primary colors or light and primary pigment colors. - Answer-
Primary colors are red, green, & blue.
Primary pigments are magenta, yellow, & cyan.
Equally mix primary colors and you get white.
Equally mix the primary pigments and you get black.
How do your eyes detect color? - Answer-Cones in your retina detect light of specific
wave lengths, which your brain detects as colors.
Red cones detect red & yellow light, green cones detect yellow and green light, blue
cones detect blue & violet light.
Light reflected from an object passes through a green filter, then a red filter, and finally a
blue filter. What color does the object appear to be? - Answer-black
, In the human eye, there are about 120,000,000 rods. If 90,000,000 rods trigger at once,
what percent of the total number of rods are triggered? - Answer-75%
The wavelengths of a color are measured in nanometers (nm), which is 0.000,000,001
meters (one billionth of a meter). Find the wave-length in meters of a light wave that has
a wave-length of 690 nm. - Answer-0.000,000,69 nm
light of one or more wavelengths that travels in more than one direction between
corresponding crests of the wave - Answer-incoherent light
light generated by heating a piece of metal until it glows - Answer-incandescent light
What is the difference between coherent and incoherent light. - Answer-coherent light:
one wavelength; one direction; constant distant between crests
incoherent light: many wavelengths, many directions, varying distance between crests
What is the process used to produce light in a laser? - Answer-Atoms in the laser tube
absorb light from a flash tube and emit light at one wavelength. Some light waves are
reflected between two mirrors and cause more atoms to emit light, resulting in a narrow,
intense light beam.
Pick the best list of uses for lasers. - Answer-read CDs, surgery, light shows, pointers
Which type of lighting device would you use for each of the following needs: - Answer-1)
economic light: fluorescent lights, 2) sign: neon lights, 3) stadium: tungsten-halogen
lights
A 25 W fluorescent light bulb emits 5.0 J of thermal energy each second. What is the
efficiency of the fluorescent light? - Answer-Eradiant = Ein - Ethermal
Efficiency = Eout/Ein
The correct answer is: 80%
If 90% of the energy emitted by an incandescent bulb is thermal energy, how much
thermal energy is emitted by a 60 W bulb each second? - Answer-54 J
a technique that produces a hologram, a complete 3-D photographic image on an object
- Answer-holography
light with a magnetic field that vibrates in only one direction - Answer-linearly polarized
light
a device that reads intensities of reflected light and converts the information to digital
signals - Answer-optical scanner
and Answers All Correct
What does an object's index of refraction indicate? - Answer-it indicates how much light
will slow down in the material compared to its speed in a vacuum
What happens to white light when it passes through a prism? - Answer-the white light
get refracted at different amounts because of its wavelength and get separated into a
rainbow
Is the lens of your eye, your finger-nail, your skin, and your tooth opaque, translucent, or
transparent? Explain. - Answer-lens is transparent because light passes through without
scattering.
Fingernails and skin are translucent because light passes through them but you cannot
see through them.
Teeth are opaque because light doesn't pass through them.
A light ray strikes a mirror at an angle of 42° from the surface of the mirror. What angle
does the ray make with normal? - Answer-48°
A ray of light hits a mirror at 27° from the normal. What is the angle between the
reflected ray and the normal? - Answer-27°
Why does a white fence appear white? - Answer-White fences reflect all colors. Your
eye sees three colors and all three get activated. The brain interprets this as white light
What color would be seen if equal amounts of red light and green light were mixed? -
Answer-yellow
Compare & contrast the primary colors or light and primary pigment colors. - Answer-
Primary colors are red, green, & blue.
Primary pigments are magenta, yellow, & cyan.
Equally mix primary colors and you get white.
Equally mix the primary pigments and you get black.
How do your eyes detect color? - Answer-Cones in your retina detect light of specific
wave lengths, which your brain detects as colors.
Red cones detect red & yellow light, green cones detect yellow and green light, blue
cones detect blue & violet light.
Light reflected from an object passes through a green filter, then a red filter, and finally a
blue filter. What color does the object appear to be? - Answer-black
, In the human eye, there are about 120,000,000 rods. If 90,000,000 rods trigger at once,
what percent of the total number of rods are triggered? - Answer-75%
The wavelengths of a color are measured in nanometers (nm), which is 0.000,000,001
meters (one billionth of a meter). Find the wave-length in meters of a light wave that has
a wave-length of 690 nm. - Answer-0.000,000,69 nm
light of one or more wavelengths that travels in more than one direction between
corresponding crests of the wave - Answer-incoherent light
light generated by heating a piece of metal until it glows - Answer-incandescent light
What is the difference between coherent and incoherent light. - Answer-coherent light:
one wavelength; one direction; constant distant between crests
incoherent light: many wavelengths, many directions, varying distance between crests
What is the process used to produce light in a laser? - Answer-Atoms in the laser tube
absorb light from a flash tube and emit light at one wavelength. Some light waves are
reflected between two mirrors and cause more atoms to emit light, resulting in a narrow,
intense light beam.
Pick the best list of uses for lasers. - Answer-read CDs, surgery, light shows, pointers
Which type of lighting device would you use for each of the following needs: - Answer-1)
economic light: fluorescent lights, 2) sign: neon lights, 3) stadium: tungsten-halogen
lights
A 25 W fluorescent light bulb emits 5.0 J of thermal energy each second. What is the
efficiency of the fluorescent light? - Answer-Eradiant = Ein - Ethermal
Efficiency = Eout/Ein
The correct answer is: 80%
If 90% of the energy emitted by an incandescent bulb is thermal energy, how much
thermal energy is emitted by a 60 W bulb each second? - Answer-54 J
a technique that produces a hologram, a complete 3-D photographic image on an object
- Answer-holography
light with a magnetic field that vibrates in only one direction - Answer-linearly polarized
light
a device that reads intensities of reflected light and converts the information to digital
signals - Answer-optical scanner
