Define it!
A transverse wave composed of an oscillating electric field and a magnetic field that oscillates perpendicular to the electric field
Electromagnetic wave
#1a SG
The eye focuses light by changing the shape of its lens. A camera focuses light by moving the position of the lens. The camera’s method is faster and much more precise.
False
(The way the eye and camera each focus is true as written. However, the special way the eye focuses light is much more efficient and effective.)
#18 SG
Sound waves cause air to oscillate. What do light waves oscillate?
Light waves oscillate a magnetic field and an electric field
(each one oscillates perpendicular to the other, as well as perpendicular to the direction of travel)
#3 SG
What does Einstein’s Special Theory of Relativity say about the speed of light?
Nothing with mass can travel faster than the speed of light
#4 SG
List these colors in order, shortest to longest wavelength:
orange, violet, yellow, green
(remember ROY G BIV where red has the longest wavelength)
Violet, green, yellow, and orange
(red is longest and violet is shortest)
#6 SG
What 2 things can happen to the direction of a light ray when it travels from one substance to another?
It can be reflected or refracted
#12 SG
The angle of reflection equals the angle of incidence
The Law of Reflection
#1b SG
A converging lens causes light rays to bend so that they converge to a single point. Diverging lenses cause light rays to bend away from each other.
True
#16 SG
Do radio waves have higher or lower frequencies than visible light?
(Remember that frequency and wavelength are inversely proportional)
Radio waves have lower frequencies than visible light
(Radio waves have longer wavelengths than visible light)
#8a SG
Light traveling through water suddenly breaks the surface and travels through air. Did the light’s speed increase, decrease, or stay the same once it left the water?
The light’s speed increased once it left the water
(Unlike sound, light travels slower in liquids than gases)
#5 SG
List these colors in order, lowest frequency to highest frequency:
orange, violet, yellow, green
(remember frequency is inversely proportional to wavelength, and ROY G BIV gives wavelength order starting with red, the longest wavelength)
Orange, yellow, green, and violet
(red is lowest and violet is highest)
#7 SG
When you look at objects underwater from above the water, they appear to be at a different position. Why?
(Remember, when light travels from water to air, it bends.)
Your mind forms a false image of the object in a slightly different location
(To see objects underwater, light must travel from the object to your eyes. When light travels from water to air, it bends.)
#14 SG
A theory of light that views light as two transverse waves, one made of an oscillating magnetic field and the other an oscillating electric field
The wave theory of light
#2a SG
As a light ray travels from air into glass, the angle that it makes with a line perpendicular to the glass surface refracts and bends toward the line.
True
(When light travels from a substance in which it moves quickly – air – to a substance in which it moves slowly – glass – the light bends towards the perpendicular.)
#13 SG
Do X-rays have higher or lower frequencies than visible light?
(Remember that frequency and wavelength are inversely proportional)
X-rays have higher frequencies than visible light
(X-rays have shorter wavelengths than visible light)
#8b SG
When objects lose heat, they give off infrared light. Since humans are almost always losing heat and giving off infrared light, why don’t we glow at night?
Infrared light is not visible
(however, there are special devices that can detect this invisible light)
#9 SG
What 3 conditions are needed for you to see a rainbow?
(Hint: Conditions must cause the light to be refracted, reflected, and refracted again. The 1st condition = water droplets suspended in the air.)
1 – Water droplets suspended in air
2 – Sun shines on them from behind you, and
3 – Sun is at a certain angle (or height in the sky)
(The water droplets cause the refraction. To see separate colors after reflection and the 2nd refraction, the light must enter the water droplet on the side from which you are viewing it.)
#15 SG
The function of a lens depends on its shape. Lens A on p. 396 curves inward like (), and Lens B curves outward like )(. Which one is converging?
Lens A, shaped like (), is a converging lens
#17a SG
A theory of light that views a ray of light as a beam of individual particles called photons
The particle theory of light
#2b SG
A shirt dyed to look violet must absorb only violet-colored light.
False
(To look violet, it must absorb all colors of light except violet. It absorbs light that is red, yellow, orange, green, blue, and indigo.)
#21 SG
Who first came up with the theory that light is a wave, around the early 1800s, and disputed Newton’s theory that light came in little packets?
Christian Huygens
(Dutch mathematician and physicist)
p. 367
Light hits a mirror, making an angle of 15 degrees relative to a line drawn perpendicular to the mirror’s surface. What angle does the reflected light make with the same line?
The reflected light also makes a 15 degree angle relative to that line
(by the Law of Reflection)
#10 SG
If the cone cells on your retina that sense red light don’t work, what color could a white piece of paper appear to be?
Blue-green or cyan
(when white light reflects off the paper and hits your eyes, only your green and blue cone cells would send signals to your brain; your brain would think you never saw red light)
#19a SG
The function of a lens depends on its shape. Lens A on p. 396 curves inward like (), and Lens B curves outward like )(. Which one is diverging?
Lens B, shaped like )(, is a diverging lens
#17b SG
A theory of light which says that light is both a particle and a wave. It is made up of individual packets that behave like particles, but the packet is actually made up of a wave.
The quantum-mechanical theory of light
#2c SG
A piece of paper is dyed to absorb all light colors except blue and green. (This dye is called “cyan” dye.) It would appear black if you put it in a dark room with red light shining on it.
True
(Since cyan absorbs all colors except blue and green, it will absorb any red light shone on it. As a result, no light will make it to your eyes.)
#21a SG
Who concluded that light requires two kinds of transverse waves oscillating perpendicular to each other - one electric and one magnetic?
James Clerk Maxwell
p. 367-368
Will a man see his foot in a mirror, despite the fact that the mirror does not reach the ground?
(Remember, the light that strikes the mirror must obey the Law of Reflection to be visible.)
Yes
(Light travels from a part of his body, reflects off the mirror, and hits his eye; his brain extends that line backwards, forming an image in the mirror.)
#11 SG
If the cone cells on your retina that sense red light don’t work, what color could a red piece of paper appear to be?
Black or gray
(When red light reflects off the paper and hits your eyes, there are no red cone cells to send color signals to your brain; the rod cells in your eyes detect the light, however, so your brain could form a grayish image.)
#19b SG
A piece of paper is dyed to absorb all light colors except blue and green. (This is called “cyan” dye.) What would you see if you put it in a dark room with green light shining on it?
Green
(Since cyan absorbs all colors except blue and green, it will reflect green light. There would be no blue.)
#21b SG