Download Worksheet 1 (Ch 13.1 p. 444

Worksheet 1 (Ch 13.1 p. 444 - 448)
(Also refer to Figure 1.3 on page 445)
1. How are frequency and wavelength related?
2. Which has a shorter wavelength: green or orange light?
3. Which has a greater frequency: yellow or blue light?
4. List the following in order of decreasing frequency: visible light, microwaves, gamma rays.
5. List the following in order of decreasing wavelength: blue light, radio, ultraviolet waves, infrared waves.
6. Which region of the electromagnetic spectrum will travel with the fastest speed?
7. If the speed of light is 3 x 108 m/s, what is the frequency of visible red light having a wavelength of 700 nanometers? (see p. 446 for example)
8. Complete the chart by filling in the missing values.
Frequency
(Hz)
Wavelength
(m)
137 x 105
498 x 10-9
5
2.11 x 1018
62 x 104
21.7 x 10-7
42.1 x 10-18
731 x 109
9.88 x 1012
64.8 x 10-2
630 nm
Spectrum Region
9. Give examples of common everyday uses of EM radiation for each part of the spectrum (see fig 1.3 p 445).
10. A light wave is an electromagnetic wave that has both an electric and magnetic component associated with it. Electromagnetic waves are often distinguished
from mechanical waves. The distinction is based on the fact that electromagnetic waves ______.
A) can travel through materials and mechanical waves cannot
B) come in a range of frequencies and mechanical waves exist with only certain frequencies
C) can travel through a region void of matter and mechanical waves cannot
D) electromagnetic waves cannot transport energy and mechanical waves can transport energy
E) electromagnetic waves have an infinite speed and mechanical waves have a finite speed
11. Explain Huygens’s Principle of wave fronts and wavelets. Draw a picture to explain (see p. 447).
12. The sun is about 150 million kilometers from Earth. Calculate how long it takes light to reach us from the sun.
13. A light-year is a unit of distance, the distance light travels in one year.
A) How many meters long is a light-year?
B) The nearest star (Proxima Centauri) is 4.2 light-years away. If you could travel in a supersonic rocket going 500 m/s, how long would it take you to travel this
distance?
14. The horsehead nebula in Orion is 1500 light-years away, the Andromeda galaxy is 2 million light- years away and the most distant quasars are over 10 billion
light-years away.
A) Is it possible to know what these objects look like right now? Why or why not?
B) It is sometimes said that telescopes are "time machines." How is this true?
15. Light and material objects always interact in one way or another. When light is incident on some materials, it is transmitted through the material. For instance,
visible light is transmitted through glass. Glass is said to be _______ to visible light.
A) transparent
B) opaque
16. Other materials absorb and/or reflect light only. They do not allow light to pass through it. Such materials are said to be
A) transparent
B) opaque
17. As light passes through transparent objects, the speed at which it travels is
A) the same speed as it travels through air
B) less than the speed at which it travels through air
C) greater than the speed at which it travels through air
Energy of EM waves (see p.738)
18. It is known that electromagnetic waves with high frequency are more capable of causing damage to the organs of living things. Which regions of the spectrum
have the tendency to cause the greatest damage to humans?
19. What is the energy of a gamma ray that has a frequency of 2 x 1020 Hz?
20. What is the energy of a radio wave that has a frequency of 100 MHz?
21. What is the energy of a microwave with a wavelength of 2 cm?
22. What is the energy of an x-ray with a wavelength of 0.1 nm?
23. How does light display the Doppler Effect? (see p. 430)
WS 2 Flat Mirrors (Ch 13.2 p. 449 – 452)
1. The diagram below contrasts the regular reflection of light off a smooth surface (left) with the diffuse reflection of light off a rough surface (right).
15
14
13
5
12
11
10
4
9
8
7
3
6
5
4
2
3
2
1
A) Compare the two diagrams and explain why the reflected rays for a rough surface do not result in the formation of an image. (For each reflected ray drawn in
the diagram above, use dashed lines to trace the reflected ray backwards behind the mirror.)
B) For the smooth surface, compare the object distance (distance from the object to the mirror) to the image distance (distance from the intersection point or
image location to the mirror).
1
1
Consider the diagram at the right in answering the next three questions.
2. The angle of incidence is denoted by angle ____.
3. The angle of reflection is denoted by angle ____.
4. If an incident ray of light makes an angle of 35° with the mirror surface then the angle of reflection is _______°.
5. Identify whether the following phenomenon are attributable to diffuse reflection (DR) or regular/specular reflection (RR):
A)
The image of a mountain can be clearly seen in the calm waters of a lake. _______
B)
A lacquered tabletop produces an image of the lamp bulb in the overhead light. _______
C) You see a glare (but no image) of the overhead light on the surface of your desk _______
D)
Light from the overhead lights strikes your body and reflects towards all your classmate's eyes. _______
6. Which one of the following diagrams depicts diffuse reflection? ________
7. True or False: When a beam of light undergoes diffuse reflection, individual rays within the beam do NOT follow the law of reflection. Explain your answer.
8. The image of an object as formed by a plane mirror is located ____.
A) on the mirror surface
C) in front of the mirror surface
B) behind the mirror surface
D) any of the above, depending on the object's location.
9. Flat mirrors produce _________ images which _________ be projected on a screen
A) real, can
C) real, can not
B) virtual, can
D) virtual, can not
10. Image location can be predicted with ____________________________________.
11. Give the symbols used for:
object distance from mirror surface: ________
image distance from mirror surface: ________
object height:
________
image height:
________
12. Images produced in flat mirrors are
A) top-bottom reversed
B) left-right reversed
C) both A and B
D) not reversed at all!
WS 3 Curved Mirrors (Ch 13.23 p. 453 – 466)
Vocabulary
A. Angle of Incidence
B. Angle of Reflection
C. Concave Mirror
D. Convex Mirror
E. Diffuse Reflection
F. Upright Image
G. Focal Length
H. Focal Point
I. Normal
J. Object
K. Principal Axis
L. Real Image
M. Regular Reflection
N. Virtual Image
1. _______This occurs when light bounces off surfaces that are not very smooth.
2. _______ An imaginary line drawn perpendicular to the surface.
3. _______ The angle that an incoming beam makes with the normal.
4. _______ An image at which light rays actually converge.
5. _______ A(n) ___ reflects light from its inwardly curving surface.
6. _______ The straight line perpendicular to the surface of a mirror at its center.
7. _______When light bounces of extremely smooth surfaces, so that the light returns to the observer in
parallel beams.
8. _______ The distance between the focal point and the mirror.
9. _______ The angle made with the normal by a beam of light that has bounced off a
surface.
10. ______ A source of diverging light rays.
11. ______ An image at which light rays do not actually converge.
12. ______ A spherical mirror that reflects light from its outwardly curving surface.
13. ______ An image that is right-side-up.
14. ______ The place at which light rays parallel to the principal axis of a concave mirror converge.
15. Explain why concave mirrors are called converging mirrors. Draw one with 2 incident (and reflected) rays.
16. Explain why convex mirrors are called diverging mirrors. Draw one with 2 incident (and reflected) rays.
17. Suppose your teacher gives you a concave mirror and asks you to find the focal point. Describe the procedure you would use to do this.
For each statement below, write true or rewrite the italicized part to make the statement true.
Concave Mirrors
.
18. _________________ Rays perpendicular to the principal axis of a concave mirror converge at or near the
focal point.
19. _________________ The focal length of a concave mirror is half the radius of curvature of the mirror.
20. _________________ Concave mirrors can produce only virtual images.
21. _________________ Concave mirrors cannot act as magnifiers.
Convex Mirrors.
22. _________________ The focal point of a convex mirror is behind the mirror.
23. _________________ Rays reflected from a convex mirror always converge.
24. _________________ The images produced by convex mirrors are real images.
25. _________________ Compared to the size of the objects, the images produced by convex mirrors are
always the same size.
RAY DIAGRAMS
1. The diagrams below show three incident rays. For each diagram, draw the three corresponding reflected rays on the diagrams. Place arrowheads on all your
rays.
2. State the three rules which describe the predictable reflection of three rays of incident light for a concave mirror. (See question #1.)
3. DRAWING RAY DIAGRAMS FOR CONCAVE MIRRORS. Use the rules above to draw ray diagrams and complete the “LOST” description of the image.
Case 1: If the object is located "beyond" the center of curvature.
Description of Image:
Location: _________________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
Case 2: If the object is located at the center of curvature.
Description of Image:
Location: ___________________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
Case 3: If the object is located
between the center of curvature and the focal point.
Description of Image:
Location: ___________________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
Case 4: If the object is located
at the focal point.
What happens to the image?
Case 5: If the object is located between the focal point and the mirror.
Description of Image:
Location: ___________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
4. DRAWING RAY DIAGRAMS FOR CONVEX MIRRORS. Use the rules above to dray ray diagrams and complete the “LOST” description of the image.
Case 1: Object is Relatively Close to Mirror
Description of Image:
Location: ________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
Case 2: Object is Relatively Far
Away from Mirror
Description of Image:
Location: ________________________
O: Upright or Inverted
S: Magnified or Reduced
T: Real or Virtual
5. Remember, rays of light are reversible.
So the rule is: If you can see me, ______________________________________________!!!
6. Explain why parabolic mirrors, rather than spherical mirrors, are used in reflecting telescopes (see p. 465-466).
Worksheet 4 Color and Polarization (Ch 13.4 p. 467 – 472)
(See also www.physicsclassroom.com , physics tutorial, Light waves and color, Lesson 1d and 2f)
1. When a light wave's are isolated to a single plane, the light is said to be
A) transverse
B) polarized
C) unpolarized
D) longitudinal
2. A Polaroid filter polarizes light by _________. a. re-orienting all the wave vibrations such that they vibrate in a single plane b. blocking part of the vibrations
while letting through those which are in a specific plane
3. Filters allow light to pass through. Polaroid filters are very selective about the orientation of the light vibrations that are allowed through. The light that passes
through a Polaroid filter is vibrating in a direction which is ____________.
A) parallel to the orientation of the molecules which make up the alignment
B) parallel to the polarization axis or transmission axis of the filter
C) parallel to the ceiling or the sky (if the source of light is on the ceiling or in the sky)
D) always horizontal, regardless of what the light source is
4. Describe the result of shining light through two polarizing filters whose transmission axes are parallel to each other. Describe the intensity and the orientation
of the emerging light.
5. Describe the result of shining light through two polarizing filters whose transmission axes are perpendicular to each other. Describe the intensity and the
orientation of the emerging light.
6. The picket fence analogy is often used to explain observations such as that in questions #4 and #5. Use the picket fence analogy to explain your answers to
questions #4 and #5. Make reference to the diagrams at right in your explanations.
7. Passing light through a Polaroid filter is not the only way that unpolarized light can be polarized. Light is also polarized when it reflects off non-metallic
surfaces. When light reflects off nonmetallic surfaces such as glass, water, or a road surface, the light is partly polarized. The reflected light consists of waves
which are vibrating mostly _____ to the reflecting surface.
A) parallel
B) perpendicular
8. Carson Busses is driving down the road on a sunny day. Reflection of light off the road surface results in a large amount of polarization and a subsequent
glare. Annoyed by the glare, Carson pulls out his Polaroid sunglasses. How must the axes of polarization be oriented in order to block the glare? (Note: the lines
on the filters below represent the axis of polarization.)
9. Electromagnetic waves also exhibits the Doppler Effect. When a distant star is approaching us, the light it emits is shifted toward the ________________ (red/
blue) end of the visible light spectrum. If the star is moving away from us, its light is shifted toward the ________________ (red/blue) end of the spectrum.
10. The redshift of all the galaxies we see tells us that
A) The universe is stationary.
B) The universe is expanding.
C) The universe is contracting.
D) There are huge black holes gobbling up all the light.
11. Using the two pictures at right to help you describe:
A) why the sky is blue during the day…
B) and why the sunsets are red/orange/yellow.