Physics Test MAY
37. TRUE or FALSE: A vibrating object is necessary for the production of sound. a. True b. False
A Absolutely! If you don't believe it, then think of some sounds - voice, guitar, piano, tuning fork, chalkboard screech, etc. - and consider what the vibrational source is. All sounds have a vibrating object of some kind as their source.
19. A filter serves the function of ____. a. subtracting color(s) from the light which is incident upon it b. adding color(s) to the light which is incident upon it c. removing nicotine from light so that we can live longer lives d. confusing physics students who are studying color, causing them to live shorter lives
A Filters can be thought of as absorbing one or more of the primary colors of light which are incident upon it, allowing remaining colors to be transmitted. For instance, a green filter will absorb all wavelengths except for green light. In this sense, filters subtract colors from the mix of incident light, allowing only selected colors to pass through.
7b. Light usually vibrates in multiple vibrational planes. It can be transformed into light vibrating in a single plane of vibration. The process of doing this is known as ____. a. translation b. interference c. polarization d. refraction
C Polarization is defined as the process of transforming unpolarized light (light whose vibrations are in a multitude of planes) into polarized light (light which can be thought of as vibrating in a single plane).
19. A pendulum makes exactly 40 vibrations in 20.0 s. Its period is ____. (Be cautious of the units.) a. 0.500 Hz. b. 0.500 s. c. 2.00 Hz. d. 2.00 s. e. 8.00 x 102 Hz.
B The period is the time for one complete cycle. If the pendulum takes 20.0 seconds for exactly 40 vibrational cycles, then it must take 0.500 second for one cycle.
14. The three secondary colors of light are ____. a. cyan, magenta, green b. cyan, magenta, and yellow c. orange, yellow, violet d. red, blue, yellow e. ... nonsense! There are more than three secondary colors of light.
B The secondary colors of light are those colors which are formed when two primary colors are mixed in equal amounts. Mixing blue and green light results in cyan light. Mixing red and blue light results in magenta light. And mixing red and green light results in yellow light.
24. If the frequency of a wave is doubled and if the speed remains constant, its wavelength is ____. a. quartered. b. halved. c. unchanged. d. doubled.
B Wave speed equals frequency*wavelength. So doubling the frequency must halve the wavelength in order for wave speed to remain the same.
35. Which phenomenon is produced when two or more waves passing simultaneously through the same medium meet up with one another? a. refraction b. diffraction c. interference d. reflection
C Interference is the meeting of two or more waves when passing along the same medium - a basic definition which you should know and be able to apply.
Diffraction
Occurs when an object causes a wave to change direction and bend around it
Microwaves
Radar
Wavelength
The distance between two corresponding parts of a wave. Distance needed to complete one wave cycle distance from the same point on 2 consecutive waves. 𝛌, depends on Frequency and wave speed.
Frequency
The number of oscillations that a wave makes in one second (hertz) how often, f, depends on vibration source
Wave
a disturbance caused by a vibration that propagates through space and time, transports ENERGY through space
Longitudinal Waves
a wave in which the particles move parallel to the path of the wave
20. Express your understanding of filters by answering the following questions. k. A blue object is illuminated with white light and viewed through a green filter. The object will appear _____. l. A cyan object is illuminated with white light and viewed through a cyan filter. The object will appear _____. m. A cyan object is illuminated with white light and viewed through a green filter. The object will appear _____. n. A yellow object is illuminated with white light and viewed through a green filter. The object will appear _____. o. A yellow object is illuminated with white light and viewed through a magenta filter. The object will appear _____.
k. RGB light (white light) hits a blue object; blue objects subtract (i.e., absorb) R and G light (when present); so B light reflects off the object and heads towards a green filter. Green filters would subtract R and B (when present) and allow G to pass through; blue light is present so it will be subtracted. So RGB - GB - B = nothing = black. l. RGB light (white light) hits a cyan object; cyan objects subtract (i.e., absorb) R light (when present); so GB light reflects off the object and heads towards a cyan filter. Cyan filters would subtract R (when present) and allow GB to pass through. So RGB - R = GB = cyan. m. RGB light (white light) hits a cyan object; cyan objects subtract (i.e., absorb) R light (when present); so GB light reflects off the object and heads towards a green filter. Green filters would subtract RB (when present) and allow G to pass through; B is present so it will be subtracted. So RGB - R - B = G = green. n. RGB light (white light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a green filter. Green filters would subtract RB (when present) and allow G to pass through; R is present so it will be subtracted. So RGB - B - R = G = green. o. RGB light (white light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a magenta filter. Magenta filters would subtract G (when present) and allow RB to pass through; G is present so it will be subtracted. So RGB - B - G = R = red.
interferance
occurs when two or more waves overlap and combine to form a new wave
Ultraviolet
sunburn
period
the time required for one cycle, a complete motion that returns to its starting point, T, inverse of frequency, Depends on vibration source
12b. TRUE or FALSE: White and black are actual colors of light. a. TRUE b. FALSE
12. TRUE or FALSE: White and black are actual colors of light. a. TRUE b. FALSE
2. If the particles of the medium are vibrating to and fro in the same direction of energy transport, then the wave is a ____ wave. a. longitudinal b. sound c. standing d. transverse
A In longitudinal waves, particles of the medium vibrate to and from in a direction parallel to the direction of energy transport. If energy is transmitted along a medium from the east end to the west end, then particles of the medium would vibrate eastward and westward A sound wave is a longitudinal wave but not the answer since a wave which exhibits this characteristic is not necessarily a sound wave.
4. A transverse wave is traveling through a medium. See diagram below. The particles of the medium are vibrating _____. there should be an image. a. parallel to the line joining AD. b. along the line joining CI. c. perpendicular to the line joining AD. d. at various angles to the line CI. e. along the curve CAEJGBI.
A In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport. In this case, that would be parallel to the line AD.
22. TRUE or FALSE: The SI unit for frequency is hertz. a. True b. False
A Know this like the back of your hand.
12. A wave X meters long passes through a medium with a speed of Y meters per second. The frequency of the wave could be expressed as a. Y/X cycles/sec. b. X/Y cycles/sec. c. XY cycles/sec. d. (X + Y) cycles/sec.
A Let d = wavelength. Since d*f = v, f = v/d.
8b. Light is passed through a Polaroid filter whose transmission axis is aligned horizontally. This will have the effect of ____. a. making the light one-half as intense and aligning the vibrations into a single plane. b. aligning the vibrations into a single plane without any effect on its intensity. c. merely making the light one-half as intense; the vibrations would be in every direction. d. ... nonsense! This will have no effect on the light itself; only the filter would be effected.
A Polaroid filters have the effect of polarizing light - that is, aligning their vibrations into a specific plane. They can be thought of as performing this feat by removing the vibrations which occur within a plane perpendicular to the transmission axis.
10. What is the amplitude of the wave in the diagram below? there should be an image. a. 0.03 m. b. 0.04 m. c. 0.05 m. d. 0.06 m.
A The amplitude of a wave is measured from rest to crest or from rest to trough; but not from crest to trough. Thus, take the 0.06 m measurement and "halve it" to get the answer.
21. TRUE or FALSE: The number of waves generated per second by a source is called the frequency of the source. a. True b. False
A This is a basic definition which you should know and be able to apply.
34. TRUE or FALSE: Constructive interference of waves occurs when two crests meet. a. True b. False
A Yes! Or when a trough meets a trough or whenever two waves displaced in the same direction (such as both up or both down) meet.
electromagnetic waves
A form of energy that can move through the vacuum of space. (no medium)
Resonance
A phenomenon that occurs when two objects naturally vibrate at the same frequency
transverse wave
A wave that moves the medium in a direction perpendicular to the direction in which the wave travels
16. Demonstrate your understanding of color addition by completing the following color equations. Options are Red, Blue, Cyan, White, Black, Magenta, Green, Yellow a. Red + Blue = _____ b. Red + Green = _____ c. Green + Blue = _____ d. Red + Blue + Green = _____ e. Blue + Yellow = _____
A. Magenta is a secondary color of light formed by combining red light with blue light in equal amounts. Refer to graphic in previous question. B. Yellow is a secondary color of light formed by combining red light with green light in equal amounts. Refer to graphic in previous question. C. Cyan is a secondary color of light formed by combining green light with blue light in equal amounts. Refer to graphic in previous question. D. White light is formed when all three primary colors of light are combined in equal amounts. E. Yellow light is a combination of red and green light. So combining blue with yellow light is like combining blue light with red and green light. The result of combining these three primary colors of light is to produce white light.
17. Demonstrate your understanding of color subtraction by completing the following color equations. a. White - Blue = _____ b. White - Red = _____ c. White - Green = _____ d. White - Blue - Green = _____ e. White - Yellow = _____ f. Red + Green - Green = _____ g. Yellow - Green = _____ h. Yellow - Red = _____ i. White - Magenta = _____ j. White - Cyan = _____ k. Yellow + Blue - Cyan = _____ l. Yellow + Cyan + Magenta = _____ m. Yellow + Cyan - Magenta = _____ n. Yellow + Cyan - Blue - Red = _____
Answer: See table above. Each of these questions is best answered by first converting any secondary color of light into a mix of two primary colors of light. Then "do the arithmetic." If the result of the "arithmetic" is a combination of two primary colors, translate the combo into a secondary color of light. Here it goes: a. White - Blue = R+G+B - B = R+G = Yellow b. White - Red = R+B+G - R = G+B = cyan c. White - Green = R+G+B - G = R+B = magenta d. White - Blue - Green = R+G+B - B - G = R = red e. White - Yellow = R+G+B - R+G = B = blue f. Red + Green - Green = R + G - G = R = red g. Yellow - Green = R+G - G = R = red (Note the similarity to part f.) h. Yellow - Red = R+G - R = G = green i. White - Magenta = R+G+B - R+B = G = green j. White - Cyan = R+G+B - G+B = R = red k. Yellow + Blue - Cyan = R+G + B - G+B = R = red (Note the similarity to part j: R+G + B is the same as white; so this question is White - Cyan.) l. Yellow + Cyan + Magenta = R+G + B+G + R+B = R+R+G+G+B+B = white + white (that is very bright white since there is double the red, green and blue added together) m. Yellow + Cyan - Magenta = R+G + B+G - R+B = G+G = green n. Yellow + Cyan - Blue - Red = R+G + G+B - B - R = G+G = green
9. As a wave passes across a boundary into a new medium, which characteristic of the wave would NOT change? a. speed b. frequency c. wavelength
B As a wave crosses a boundary into a new medium, its speed and wavelength change while its frequency remains the same.
23. TRUE or FALSE: Doubling the frequency of a wave source (without altering the medium) doubles the speed of the waves. a. True b. False
B Don't be fooled. Wave speed may equal frequency*wavelength. Yet doubling the frequency only halves the wavelength; wave speed remains the same. To change the wave speed, the medium would have to be changed.
14. If the distance from point A to point B in the diagram is 60 cm, then the wavelength is ____. a. 20 cm. b. 40 cm. c. 60 cm. d. 90 cm.
B From point A to point E is one full wave cycle. This distance represents two-thirds of the 60 cm from A to G. Thus, the wavelength is (2/3)*60 cm = 40 cm.
5. If the energy in a longitudinal wave travels from south to north, the particles of the medium would be vibrating _____. a. from north to south, only b. both north and south c. from east to west, only d. both east and west
B In longitudinal waves, particles of the medium vibrate to and from in a direction parallel to the direction of energy transport. If the particles only moved north and not back south, then the particles would be permanently displaced from their rest position; this is not wavelike.
17. What is the frequency of a wave that has a speed of 0.4 m/s and a wavelength of 0.020 meter? a. 10 hertz. b. 20 hertz. c. 0.008 hertz. d. 0.5 hertz.
B Let w=wavelength; then v = w*f. In this problem, it is given that v=5 m/s and w = .02 m. Substitution and algebra yields f=v/w=20 Hz.
18. Sunsets often have a reddish-orange color associated with them. This is attributable to the phenomenon of _____. a. polarization b. diffraction c. dispersion d. refraction
B Sunsets are the result of the longer wavelengths of light diffracting around atmospheric particles and reaching our eyes, giving the reddish-orange appearance. More detail about the phenomenon can be accessed using the Useful Web Link below.
9b. Light is passed through a Polaroid filter whose transmission axis is aligned horizontally. It then passes through a second filter whose transmission axis is aligned vertically. After passing through both filters, the light will be ______. a. polarized b. unpolarized c. entirely blocked d. returned to its original state.
C The first filter serves the role of blocking one-half the light; the horizontal vibrations would emerge from the filter and the vertical vibrations would be blocked. The second filter would allow the vertical vibrations to pass through if there were any. However, since the vertical vibrations have already been filtered out, there is no light remaining after the second filter is used. This combination of two filters serves to block all the light.
20. A period of 0.005 seconds would be equivalent to a frequency of ____ Hz. a. 20 b. 50 c. 200 d. 500 e. 2000
C The period and the frequency are related by a reciprocal relationship; that is, f = 1/T.
6. As a pulse travels though a uniform medium, the speed of the pulse ____. a. decreases b. increases c. remains the same
C The speed of a wave or a pulse depends upon the properties of the medium. If the medium is uniform or unchanging, then the speed is constant.
6b. Light which is vibrating in a variety of planes is referred to as _____ light a. electromagnetic b. transverse c. unpolarized d. polarized
C Unpolarized light is light whose vibrations are in a multitude of directions.
13. The three primary colors of light are ____. a. white, black, gray b. blue, green, yellow c. red, blue, green d. red, blue, yellow e. ... nonsense! There are more than three primary colors of light.
C Yes, you must know this one! It forms the basis of most of our logic and reasoning about color, light and the appearance of objects.
13. How many complete waves are shown in the diagram? a. 1 b. 2 c. 3 d. 1.5
D From point A to point E is one full wave cycle. After point E, the wave begins to repeat itself, but only for one-half of a cycle. Thus, there are 1.5 waves shown in the diagram.
3. When the particles of a medium are vibrating at right angles to the direction of energy transport, then the wave is a ____ wave. a. longitudinal b. sound c. standing d. transverse
D In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.
16. A periodic and repeating disturbance in a lake creates waves which emanate outward from its source to produce circular wave patterns. If the frequency of the source is 2.00 Hz and the wave speed is 5.00m/s then the distance between adjacent wave crests is ___ meter. a. 0.200 b. 0.400 c. 1.25 d. 2.50 e. 10.0
D Let w=wavelength; then v = w*f. In this problem, it is given that v=5.00 m/s and f = 2.00 Hz. Substitution and algebra yields w = v / f = 2.50 m.
7. The main factor which effects the speed of a sound wave is the ____. a. amplitude of the sound wave b. intensity of the sound c. loudness of the sound d. properties of the medium e. pitch of the sound
D The speed of a wave is dependent upon the properties of the medium and not the properties of the wave.
11. The wavelength of the wave in the diagram above (Question #10) is ____ m. a. 0.030 b. 0.040 c. 0.060 d. 0.080
D The wavelength of a wave is measured as the distance between any two corresponding points on adjacent waves, which would mean from a crest to the next adjacent crest. Thus, the distance from point b to point d is the wavelength - 0.08 m
15. The number of cycles of a periodic wave occurring per unit time is defined as a wave's ____. a. wavelength. b. period. c. amplitude. d. frequency.
D This is a basic definition which you should know and be able to apply.
5b. Light which is vibrating in a single plane is referred to as _____ light a. electromagnetic b. transverse c. unpolarized d. polarized
D Unpolarized light is light whose vibrations are in a multitude of directions. To simplify matters, unpolarized light is light which can be thought of as vibrating in a vertical and a horizontal plane. If one of these planes of vibration is removed, then light would be vibrating in a single plane and said to be "polarized."
36. Two pulses are traveling in opposite directions along the same medium as shown in the diagram at the right. Which diagram below best depicts the appearance of the medium when each pulse meets in the middle? there should be a picture
D When a crest is completely overlapped with a trough having the same amplitude, destructive interference occurs. Complete cancellation takes place if they have the same shape and are completely overlapped.
15. Combining red and green light (with equal intensity) makes ____ light; combining red and blue light (with equal intensity) makes ____ light; and combining blue and green light (with equal intensity) makes ____ light. Choose the three colors in respective order. a. brown, purple, aqua b. brown, magenta, yellow c. yellow, magenta, brown d. yellow, magenta, cyan
D there should be a picture here You must know this for it forms the foundation of much of our reasoning. To assist in recalling the three primary colors of light, three secondary colors of light, and the means by which adding primaries form secondaries, develop some form of graphical reminder such as a color wheel or a diagram like those at the right.
1. A single Disturbance that movers from point to point through a medium is called a ... a. period b. periodic wave c. wavelength d. pulse
D pulse A wave is a continuous and repeating disturbance of a medium and a pulse is a single disturbance.
38. Which one of the following CANNOT transmit sound? a. Liquid air b. Gaseous oxygen c. Liquid water d. Solid steel e. Perfect vacuum
E Sound is a mechanical wave and as such requires a medium in order to move through space. For this reason, sound cannot move through a vacuum.
Radio Waves
Electromagnetic waves with the longest wavelengths and lowest frequencies Example: GPS
Gamma Rays
Kill cancerous cells and normal cells.
Amplitude
Maximum distance that the wave travels from its rest position ( meters) How high? depends on energy input
polarization of light
The aligning of vibrations in a transverse wave, usually by filtering out waves of other directions
Refraction
The bending of a wave as it passes at an angle from one medium to another
Reflection
The bouncing back of a wave when it hits a surface through which it cannot pass.
Wave speed
The speed at which the wave propagates through space ( meters/seconds) how fast? depends on the medium
20. Express your understanding of filters by answering the following questions. a. A red filter is capable of transmitting ____ light (if it is incident upon the filter). b. A blue filter is capable of transmitting ____ light (if it is incident upon the filter). c. A green filter is capable of transmitting ____ light (if it is incident upon the filter). d. A red filter will absorb ____ light (if it is incident upon the filter). e. A blue filter will absorb ____ light (if it is incident upon the filter).
a. Red filters absorb cyan light (the complementary color of red). If white light (red + blue + green) shines on a red filter and cyan (blue + green) light is absorbed, all that is left to be transmitted is red light. b. Blue filters absorb yellow light (the complementary color of blue). If white light (red + blue + green) shines on a blue filter and yellow (red + green) light is absorbed, all that is left to be transmitted is blue light. c. Green filters absorb magenta light (the complementary color of green). If white light (red + blue + green) shines on a green filter and magenta (red + blue) light is absorbed, all that is left to be transmitted is green light. d. Red filters absorb its complementary color - cyan. So this question could be answered as cyan. And since cyan light consists of blue + green light, this question could also be answered as blue + green. e. Blue filters absorb its complementary color - yellow. So this question could be answered as yellow. And since yellow light consists of red + green light, this question could also be answered as red + green.
20. Express your understanding of filters by answering the following questions. f. A yellow filter will absorb ____ light (if it is incident upon the filter). g. A magenta filter will absorb ____ light (if it is incident upon the filter). h. A white object is illuminated with white light and viewed through a green filter. The object will appear _____. i. A white object is illuminated with white light and viewed through a blue filter. The object will appear _____. j. A white object is illuminated with white light and viewed through a cyan filter. The object will appear _____.
f. Yellow filters absorb its complementary color - blue. So this question must be answered as blue. g. Magenta filters absorb its complementary color - green. So this question must be answered as green. h. RGB light (white light) hits a white object; white objects do not subtract (i.e., absorb) any colors; so RGB reflects off the object and heads towards a green filter. Green filters would subtract R and B (when present) and allow G to pass through. So RGB - nothing - GB = R = red. i. RGB light (white light) hits a white object; white objects do not subtract (i.e., absorb) any colors; so RGB reflects off the object and heads towards a blue filter. Blue filters would subtract R and B (when present) and allow B to pass through. So RGB - nothing - RG = B = blue. j. RGB light (white light) hits a white object; white objects do not subtract (i.e., absorb) any colors; so RGB reflects off the object and heads towards a cyan filter. Cyan filters would subtract R (when present) and allow G to pass through. So RGB - nothing - R = GB = cyan.
Don't forget to do 28. It is the last one on the review doc, link to answers on other side
https://www.physicsclassroom.com/reviews/light/Light-and-Color-Review-Answers-3
20. Express your understanding of filters by answering the following questions. p. A yellow object is illuminated with yellow light and viewed through a yellow filter. The object will appear _____. q. A yellow object is illuminated with yellow light and viewed through a blue filter. The object will appear _____. r. A yellow object is illuminated with blue light and viewed through a yellow filter. The object will appear _____. s. A blue object is illuminated with blue light and viewed through a yellow filter. The object will appear _____. t. A yellow object is illuminated with yellow light and viewed through a red filter. The object will appear _____.
p. RG light (yellow light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a yellow filter. Yellow filters would subtract B (when present) and allow RG to pass through. So RG - nothing - nothing = RG = yellow. q. RG light (yellow light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a blue filter. Blue filters would subtract RG (when present) and allow B to pass through; R and G are both present so they will be subtracted. So RG - nothing - RG = nothing = black. r. B light (blue light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so no light light reflects off the object and it wouldn't matter what type of filter is used. This object will appear black. So B - B - nothing = nothing = black. s. B light (blue light) hits a blue object; blue objects subtract (i.e., absorb) RG light (when present); so B light reflects off the object and heads towards a yellow filter. Yellow filters would subtract B (when present) and allow RG to pass through (if present); neither R nor G are present and the B gets subtracted. So B - nothing - B = nothing = black. t. RG light (yellow light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a red filter. Red filters would subtract GB (when present) and allow R to pass through (if present); G is present so it gets subtracted. So RG - nothing - G = R = red.
Electromagnetic Spectrum
radio waves, microwaves, infared waves, visible light, ultraviolet waves, xrays, and gamma rays
Infrared Radiation
space heater
20. Express your understanding of filters by answering the following questions. u. A yellow object is illuminated with yellow light and viewed through a green filter. The object will appear _____. v. A yellow object is illuminated with green light and viewed through a yellow filter. The object will appear _____. w. A yellow object is illuminated with green light and viewed through a green filter. The object will appear _____.
u. RG light (yellow light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so RG light reflects off the object and heads towards a green filter. Green filters would subtract RB (when present) and allow G to pass through (if present); R is present so it gets subtracted. So RG - nothing - R = G = green. v. G light (green light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so G light reflects off the object and heads towards a yellow filter. Yellow filters would subtract B (when present) and allow RG to pass through (if present). So G - nothing - nothing = G = green. w. G light (green light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so G light reflects off the object and heads towards a green filter. Green filters would subtract RB (when present) and allow G to pass through (if present). So G - nothing - nothing = G = green.
X-rays
used to take images of the human body using an X-ray machine
Mechanical Waves
waves that require a medium through which to travel
20. Express your understanding of filters by answering the following questions. x. A yellow object is illuminated with green light and viewed through a red filter. The object will appear _____. y. A yellow object is illuminated with green light and viewed through a cyan filter. The object will appear _____. z. A red object is illuminated with yellow light and viewed through a cyan filter. The object will appear _____.
x. G light (green light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so G light reflects off the object and heads towards a red filter. Red filters would subtract GB (when present) and allow R to pass through (if present); G is present so it gets subtracted. So G - nothing - G = nothing = black. y. G light (green light) hits a yellow object; yellow objects subtract (i.e., absorb) B light (when present); so G light reflects off the object and heads towards a cyan filter. Cyan filters would subtract R (when present) and allow GB to pass through (if present). So G - nothing - nothing = G= green. z. G light (green light) hits a red object; red objects subtract (i.e., absorb) GB light (when present). G is present so it gets subtracted and it wouldn't matter what filter is used to view this object; there is no light reflecting off the object so it will appear black. So G - G - nothing = nothing = black.