Unit 10 Physics: Electromagnetic Waves PSA
Name _____________________________
1) When the speed of a wave is constant, how does increasing the frequency affect the wavelength?
A) it increases wavelength
B) it decreases wavelength
C) the wavelength stays constant
D) cannot be determined
2) Rank the following types of electromagnetic radiation from shortest wavelength to highest wavelength:
ultraviolet, infrared, radio, microwave, gamma rays, red light, blue light, green light, violet light
Shortest
wavelength
Gamma
Rays
Ultraviolet
Violet
Light
Blue
Light
Green
Light
Red
Light
Infrared
Microwave
Radio
Longest
Wavelength
3) Rank the following types of electromagnetic radiation from highest energy to lowest energy:
ultraviolet, infrared, radio, microwave, gamma rays, red light, blue light, green light, violet light
Shortest
Gamma
Ultraviolet Violet Blue
Green Red
Infrared Microwave Radio Longest
wavelength Rays
Light
Light Light
Light
Wavelength
4) What happens to the energy of an electromagnetic wave when the frequency increases?
A) energy increases
B) energy decreases
C) energy stay the same
D) can not be determined
5) Determine the speed of light for a green laser beam with a wavelength of 5.32 x 10-7 meters in a vacuum.
3.00 x 108 m/s
6) The shortest wavelengths of visible light are seen as _______violet__________ light.
7) ____gamma rays________________ waves are associated with heat radiation emitted by living human or
animal bodies and are just longer than waves in the visible spectrum.
8) _____ultraviolet_______________ waves cause damage to living tissue and are just shorter than waves in the
visible spectrum.
9) All light waves travel at a constant speed of ______3.00 x 108___________ m/s in a vacuum.
10) All light waves can be classified as: (Mark all that apply)
A) longitudinal
B) transverse
C) mechanical
D) non-mechanical
11) You are wearing a fluorescent yellow shirt. What is happening to the colors of sunlight incident on the shirt?
A) The shirt is absorbing all colors.
B) The shirt is reflecting all colors.
C) The shirt is absorbing yellow light and reflecting all other colors of light.
D) The shirt is reflecting yellow light and absorbing all other colors of light.
12) Specular reflection describes reflection of light off a _____smooth__________ surface whereas diffuse
reflection describes reflection off a _______rough____________ surface.
13) The reflected image seen in a flat (plane) mirror is: (Mark all that correctly apply.)
A) Real
B) Virtual C) Upright
D) Inverted
E) Enlarged
F) Reduced
G) Same size
14) A green light ray travels from water to air at incident angle of 40o. In the air, the refracted light ray
will_________________________:
A) speed up and bend away from the normal
C) speed up and bend towards the normal
B) slow down and bend away from the normal
D) slow down and bend away from the normal
15) During refraction, if the refracted light wave is bending closer toward the normal line then the light wave
________________________.
A) is moving faster than before
B) is moving slower than before
C) is moving at the same speed
D) has more energy than before
16) If an incident light ray is going from a more dense medium into a less dense medium at an angle of 42° (to the
normal), then the refracted light ray might be:
A) 42°
B) 39°
C) 45°
D) 21°
E) 0° further from normal is faster
17) An incident light ray (the arrow) is being refracted from more optically
dense medium to a less optically dense medium. On the
picture to the right, draw a normal line and draw an
approximate refracted ray.
Does the refracted ray bend further or closer to the normal
Less Optically Dense
than the incident ray. __bends further from normal_______
More Optically Dense
When compared to the incident light ray, is the refracted light
ray moving faster or slower than the incidence ray? ___It
moves faster____________________
18) The type of image produced by a convex lens depends on:
A) The size of the object
B) the diameter of the lens
C) which side of the lens the object is
D) which side of the axis the object is (that is, oriented up or down)
E) the position of the object with respect to the center of the lens and its focal point
19) A 1.5 cm tall object is placed 6.0 cm in front of a convex lens having a focal length of 4.0 cm. Draw a ray
diagram to locate the image. Draw the lens in the middle first.
Then label all the f and 2f points.
Your drawing MUST be to scale and use a ruler.
Describe the type of image formed: real or virtual
upright or inverted
enlarged, same size, or reduced
Convex Lens
8cm
2F
4cm
obj
F
4cm
8cm
F
2F
image
20) Using the focal length equation, calculate the focal length when the distance to image is 10.0 cm and the
distance to the object is 20.0 cm. (GUESS METHOD HELPS HERE!!!!!)
Diagram: (Given + Unknowns)
f = ???? cm
di = 10 cm
do = 20 cm
Equation: 1
= 1 + 1
di
do
Substitute: : 1 = 1 + 1
f
di
do
f
1
f
= 1 +
10
1
20
1
f
= 0.1 + 0.05
1 = 0.15
f
(DO A SWITCHAROO)
1
= f
0.15
Solve: f = 6.67 cm
21) Which one of the following statements about lens images is true?
A) Real images are always inverted, while virtual images are always upright
B) Real images are always upright, while virtual images are always inverted.
C) Real and virtual images are always upright.
D) Real and virtual images are always inverted.
22) Name 5 wave interactions that support light acting like a wave. Reflection, refraction, diffraction,
polarization, interference
23) Name 3 pieces of evidence that support light acting as a particle of energy (called a photon).
***** photoelectric effect, emission spectra, ********* and blackbody radiation
24) When the frequency of a photon increases, what happens to the energy of the photon?
A) Photon energy increases
B) Photon energy decreases.
C) Enough energy exists to transform it into an electron
D) Photon energy remains constant.
25) What occurs when an electromagnetic wave of frequency = 2.5 x 1015 Hz hits a sample of lead (Pb) with a
threshold frequency = 1.03 x 1015 Hz?
A) Electrons are ejected instantaneously.
B) Electrons are absorbed instantaneously.
C) Electrons become polarized.
D) Actually nothing happens.