Question 1

The direction of polarization of an electromagnetic wave is taken by convention to be

Accepted Answer

A)  the electric field direction. 
B)  the magnetic field direction. 
C)  the direction of E × B. 
D)  perpendicular to the electric field direction. 
E)  None of these choices are correct. 
A)  the electric field direction. 
B)  the magnetic field direction. 
C)  the direction of E × B. 
D)  perpendicular to the electric field direction. 
E)  None of these choices are correct.

Question 2

What color would an EM wave with a frequency of 430 THz be?

Accepted Answer

A)  blue 
B)  green 
C)  yellow 
D)  red 
E)  not in the visible range 
A)  blue 
B)  green 
C)  yellow 
D)  red 
E)  not in the visible range

Question 3

It is possible to detect Doppler shifts in the light emitted from each side of a rapidly spinning star. Suppose the light from a nearby star of radius 2.5 × 108 km is blue-shifted on one side of the star and red-shifted on the other side. Assume the center of mass of the star is stationary relative to Earth. If the star emits light of wavelength 525 nm that is shifted, in the received light, to 523 nm on one side of the star and to 527 nm on the other side, what is the rotational period of the star?

Accepted Answer

A)  34 days 
B)  32 days 
C)  24 days 
D)  16 days 
A)  34 days 
B)  32 days 
C)  24 days 
D)  16 days

Question 4

Electromagnetic wavelengths of a few centimeters are classified as what type of radiation?

Accepted Answer

A)  visible light 
B)  ultraviolet 
C)  microwaves 
D)  radio waves 
E)  gamma rays 
A)  visible light 
B)  ultraviolet 
C)  microwaves 
D)  radio waves 
E)  gamma rays

Question 5

In vacuum, the components of an EM wave are Ey = (50 V/m) cos [(5.00 m−1)x + ωt], Ex = 0, and Ez = 0. What is ω?

Accepted Answer

A)  1.50 × 109 rad/s 
B)  l.20 × 109 rad/s 
C)  1.00 × 109 rad/s 
D)  8.00 × 108 rad/s 
E)  More information is needed. 
A)  1.50 × 109 rad/s 
B)  l.20 × 109 rad/s 
C)  1.00 × 109 rad/s 
D)  8.00 × 108 rad/s 
E)  More information is needed.

Question 6

Light of 10 cm wavelength is classified as what type of radiation?

Accepted Answer

A)  gamma ray 
B)  x-ray 
C)  UV 
D)  microwave 
E)  visible 
A)  gamma ray 
B)  x-ray 
C)  UV 
D)  microwave 
E)  visible

Question 7

Your favorite radio station is located due north of your house and broadcasts using a horizontal electric dipole antenna directed north-south. To receive this signal you need to

Accepted Answer

A)  move to a town that is farther to the east or west. 
B)  use a magnetic dipole antenna instead of an electric dipole antenna. 
C)  orient the receiving antenna horizontally north-south. 
D)  use a vertical receiving antenna. 
A)  move to a town that is farther to the east or west. 
B)  use a magnetic dipole antenna instead of an electric dipole antenna. 
C)  orient the receiving antenna horizontally north-south. 
D)  use a vertical receiving antenna.

Question 8

The background radiation in space corresponds to blackbody radiation of what temperature?

Accepted Answer

A)  0 K 
B)  2.7 K 
C)  273 K 
D)  5800 K 
E)  98.6°F 
A)  0 K 
B)  2.7 K 
C)  273 K 
D)  5800 K 
E)  98.6°F

Question 9

What is the wavelength from a radio station having frequency 108 MHz?

Accepted Answer

A)  2.78 m 
B)  27.8 m 
C)  32.3 m 
D)  323 m 
E)  108 m 
A)  2.78 m 
B)  27.8 m 
C)  32.3 m 
D)  323 m 
E)  108 m

Question 10

Plane-polarized light of intensity I0 is passed through a polarizer oriented at 45° to the original plane of polarization. What is the intensity transmitted?

Accepted Answer

A)  0.70 I0 
B)  0.50 I0 
C)  0.35 I0 
D)  0.25 I0 
E)  0.00 
A)  0.70 I0 
B)  0.50 I0 
C)  0.35 I0 
D)  0.25 I0 
E)  0.00

Question 11

What is the intensity of the electromagnetic radiation 2.00 m from a 100 W isotropic source?

Accepted Answer

A)  25.0 W/m2 
B)  6.25 W/m2 
C)  4.00 W/m2 
D)  1.99 W/m2 
E)  1.00 W/m2 
A)  25.0 W/m2 
B)  6.25 W/m2 
C)  4.00 W/m2 
D)  1.99 W/m2 
E)  1.00 W/m2

Question 12

At the summer solstice in June, at what latitude is the Sun directly overhead at solar noon?

Accepted Answer

A)  0.0° (the equator) 
B)  23.5° N 
C)  23.5° S 
D)  66.5° N 
E)  40.0° N 
A)  0.0° (the equator) 
B)  23.5° N 
C)  23.5° S 
D)  66.5° N 
E)  40.0° N

Question 13

How fast would you have to drive in order to see a red light as green? Assume λ = 630 nm for red and λ = 530 nm for green.

Accepted Answer

A)  5 × 107 m/s 
B)  5 × 106 m/s 
C)  5 × 105 m/s 
D)  5 × 104 m/s 
A)  5 × 107 m/s 
B)  5 × 106 m/s 
C)  5 × 105 m/s 
D)  5 × 104 m/s

Question 14

The Sun has a radius of 6.955 × 108 km and a rotational period of 25.38 days. What is the difference in the wavelength of the peak of the observed spectrum between light received from the approaching side of the Sun and from the receding side of the Sun? Observations of the middle of the Sun place the spectral peak at 480 nm.

Accepted Answer

A)  13 nm 
B)  6.4 nm 
C)  1.6 nm 
D)  3.2 nm 
A)  13 nm 
B)  6.4 nm 
C)  1.6 nm 
D)  3.2 nm

Question 15

If the wavelength of light is 400 nm in a substance where the speed of light is 2.35 × 108 m/s, what is the wavelength of this light in air?

Accepted Answer

A)  313 nm 
B)  400 nm 
C)  511 nm 
D)  635 nm 
E)  940 nm 
A)  313 nm 
B)  400 nm 
C)  511 nm 
D)  635 nm 
E)  940 nm

Question 16

An electromagnetic wave with a wavelength about the same as the diameter of an apple would be

Accepted Answer

A)  an x-ray. 
B)  UV. 
C)  infrared. 
D)  a microwave. 
E)  a radio wave. 
A)  an x-ray. 
B)  UV. 
C)  infrared. 
D)  a microwave. 
E)  a radio wave.

Question 17

Household wiring can emit electromagnetic waves of frequency 60 Hz. What is the wavelength of these waves?

Accepted Answer

A)  5.0 × 102 m 
B)  5.0 × 103 m 
C)  5.0 × 104 m 
D)  5.0 × 105 m 
E)  5.0 × 106 m 
A)  5.0 × 102 m 
B)  5.0 × 103 m 
C)  5.0 × 104 m 
D)  5.0 × 105 m 
E)  5.0 × 106 m

Question 18

The wavelengths associated with thermal radiation at everyday temperatures are in which spectral region?

Accepted Answer

A)  infrared 
B)  ultraviolet 
C)  shorter visual 
D)  longer visual 
E)  x-ray 
A)  infrared 
B)  ultraviolet 
C)  shorter visual 
D)  longer visual 
E)  x-ray

Question 19

Nexrad radar uses electromagnetic radiation of frequency of 2.7 GHz to measure the speed of cloud systems. Radio waves from a transmitter are sent outward toward a cloud system, and the waves are reflected back toward the source. If the cloud system is moving, the reflected waves will be Doppler shifted. Suppose a Nexrad system observes clouds moving toward the transmitter at 21 m/s. What is the difference between the transmitted and received frequencies of the radar in this case?

Accepted Answer

A)  380 Hz 
B)  760 Hz 
C)  570 Hz 
D)  190 Hz 
A)  380 Hz 
B)  760 Hz 
C)  570 Hz 
D)  190 Hz

Question 20

Unpolarized light of intensity I0 is sent through an arrangement of 4 polarizers. Each polarizer (after the first) is rotated 30° relative to the preceding one, so that the last polarizer is perpendicular to the first. What is the intensity transmitted by this system?

Accepted Answer

A)  0.75 I0 
B)  0.50 I0 
C)  0.42 I0 
D)  0.21 I0 
E)  0 
A)  0.75 I0 
B)  0.50 I0 
C)  0.42 I0 
D)  0.21 I0 
E)  0

Exam 22: Electromagnetic Waves

The direction of polarization of an electromagnetic wave is taken by convention to be

What color would an EM wave with a frequency of 430 THz be?

Electromagnetic wavelengths of a few centimeters are classified as what type of radiation?

In vacuum, the components of an EM wave are Ey = (50 V/m) cos [(5.00 m−1)x + ωt], Ex = 0, and Ez = 0. What is ω?

Light of 10 cm wavelength is classified as what type of radiation?

Your favorite radio station is located due north of your house and broadcasts using a horizontal electric dipole antenna directed north-south. To receive this signal you need to

The background radiation in space corresponds to blackbody radiation of what temperature?

What is the wavelength from a radio station having frequency 108 MHz?

Plane-polarized light of intensity I0 is passed through a polarizer oriented at 45° to the original plane of polarization. What is the intensity transmitted?

What is the intensity of the electromagnetic radiation 2.00 m from a 100 W isotropic source?

At the summer solstice in June, at what latitude is the Sun directly overhead at solar noon?

How fast would you have to drive in order to see a red light as green? Assume λ = 630 nm for red and λ = 530 nm for green.

If the wavelength of light is 400 nm in a substance where the speed of light is 2.35 × 108 m/s, what is the wavelength of this light in air?

An electromagnetic wave with a wavelength about the same as the diameter of an apple would be

Household wiring can emit electromagnetic waves of frequency 60 Hz. What is the wavelength of these waves?

The wavelengths associated with thermal radiation at everyday temperatures are in which spectral region?

Unpolarized light of intensity I0 is sent through an arrangement of 4 polarizers. Each polarizer (after the first) is rotated 30° relative to the preceding one, so that the last polarizer is perpendicular to the first. What is the intensity transmitted by this system?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Alternating Current

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

In vacuum, the components of an EM wave are E_y = (50 V/m) cos [(5.00 m⁻¹)x + ωt], E_x = 0, and E_z = 0. What is ω?

Plane-polarized light of intensity I₀ is passed through a polarizer oriented at 45° to the original plane of polarization. What is the intensity transmitted?

If the wavelength of light is 400 nm in a substance where the speed of light is 2.35 × 10⁸ m/s, what is the wavelength of this light in air?

Unpolarized light of intensity I₀ is sent through an arrangement of 4 polarizers. Each polarizer (after the first) is rotated 30° relative to the preceding one, so that the last polarizer is perpendicular to the first. What is the intensity transmitted by this system?