Question 1

The maximum value of the magnetic field component of an electromagnetic wave is 2.81 μT. What is the rms value of the magnetic field?

Accepted Answer

A)  2.81 μT 
B)  2.46 μT 
C)  3.12 μT 
D)  3.97 μT 
E)  1.99 μT 
A)  2.81 μT 
B)  2.46 μT 
C)  3.12 μT 
D)  3.97 μT 
E)  1.99 μT

Question 2

A 60.0 W light bulb radiates light uniformly in all different directions. What is the value of E at a distance of 0.400 m from the bulb?

Accepted Answer

A)  162 N/C 
B)  212 N/C 
C)  82.1 N/C 
D)  106 N/C 
E)  52.9 N/C 
A)  162 N/C 
B)  212 N/C 
C)  82.1 N/C 
D)  106 N/C 
E)  52.9 N/C

Question 3

The total electromagnetic power emitted by the Sun is 3.8 ×1026 W. What is the radiation pressure near the orbit of Mercury, which has an orbital radius of 5.8 × 1010 m?

Accepted Answer

Question 4

How far does a beam of light travel in one full year?

Accepted Answer

A)  80 × 1012 m 
B)  95 × 1014 m 
C)  30 × 108 m 
D)  20 × 1015 m 
E)  36 × 1016 m 
A)  80 × 1012 m 
B)  95 × 1014 m 
C)  30 × 108 m 
D)  20 × 1015 m 
E)  36 × 1016 m

Question 5

The wavelength of a certain portion of microwaves is 40 mm. What is its frequency?

Accepted Answer

A)  40 GHz 
B)  4.0 GHz 
C)  0.75 GHz 
D)  75 GHz 
E)  7.5 GHz 
A)  40 GHz 
B)  4.0 GHz 
C)  0.75 GHz 
D)  75 GHz 
E)  7.5 GHz

Question 6

In Fizeau's experiment to measure the speed of light, the wheel has 475 notches and rotates with a speed of 40.0 rev/sec. Light passing through one notch travels to the mirror and back just in time to pass through the next notch. If the distance between the wheel and the mirror is 7890 m, what is the speed of light measured by this experiment?

Accepted Answer

A)  3.00 × 108 m/s 
B)  3.00 × 10-8 m/s 
C)  3.22 × 108 m/s 
D)  3.22 × 10-8 m/s 
E)  2.25 × 108 m/s 
A)  3.00 × 108 m/s 
B)  3.00 × 10-8 m/s 
C)  3.22 × 108 m/s 
D)  3.22 × 10-8 m/s 
E)  2.25 × 108 m/s

Question 7

Electromagnetic waves are a result of a stationary electric field and a changing magnetic field.

Accepted Answer

A) True 
 B)False

Question 8

A car is going past a radio station at a speed of 40.0 m/s. If the radio station broadcasts at a frequency of 74.5 MHz, what change in frequency does the driver observe?

Accepted Answer

A)  9.93 Hz 
B)  99.3 Hz 
C)  993 Hz 
D)  7.45 Hz 
E)  74.5 Hz 
A)  9.93 Hz 
B)  99.3 Hz 
C)  993 Hz 
D)  7.45 Hz 
E)  74.5 Hz

Question 9

The electric energy density in an electromagnetic wave is higher than its magnetic energy density.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following represents the maximum value of the magnetic field at a distance of 2.5 m from a 100 W light bulb?

Accepted Answer

A)  0.10 μT 
B)  0.40 μT 
C)  0.50 μT 
D)  0.60 μT 
E)  0.80 μT 
A)  0.10 μT 
B)  0.40 μT 
C)  0.50 μT 
D)  0.60 μT 
E)  0.80 μT

Question 11

An electromagnetic wave is propagating towards the west. At a certain moment the direction of the magnetic field vector associated with this wave points vertically up. What is the direction of the electric field vector?

Accepted Answer

A)  Horizontal and pointing south 
B)  Vertical and pointing down 
C)  Horizontal and pointing north 
D)  Vertical and pointing up 
E)  Horizontal and pointing east 
A)  Horizontal and pointing south 
B)  Vertical and pointing down 
C)  Horizontal and pointing north 
D)  Vertical and pointing up 
E)  Horizontal and pointing east

Question 12

A car is approaching a radio station at a speed of 25.0 m/s. If the radio station broadcasts at a frequency of 74.5 MHz, what change in frequency does the driver observe?

Accepted Answer

A)  98.3 Hz 
B)  6.21 Hz 
C)  726 Hz 
D)  67.0 Hz 
E)  64.5 Hz 
A)  98.3 Hz 
B)  6.21 Hz 
C)  726 Hz 
D)  67.0 Hz 
E)  64.5 Hz

Question 13

A radio station broadcasts at 80 MHz. How long does it take for this radio signal to travel a distance of 20 × 106 m?

Accepted Answer

A)  0.15 × 10-2 s 
B)  15 ms 
C)  6.7 × 10-2 s 
D)  20 ms 
E)  25 ms 
A)  0.15 × 10-2 s 
B)  15 ms 
C)  6.7 × 10-2 s 
D)  20 ms 
E)  25 ms

Question 14

The speed of electromagnetic waves through a vacuum is ten times the speed of sound in air.

Accepted Answer

A) True 
 B)False

Question 15

The average intensity of the sunlight in Miami, Florida, is 1040 W/m2. What is the average value of the radiation pressure due to this sunlight in Miami?

Accepted Answer

A)  2.28 × 10-6 N/m2 
B)  1.63 × 10-6 N/m2 
C)  7.83 × 10-6 N 
D)  3.46 × 10-6 N/m2 
E)  9.78 × 10-6 N/m2 
A)  2.28 × 10-6 N/m2 
B)  1.63 × 10-6 N/m2 
C)  7.83 × 10-6 N 
D)  3.46 × 10-6 N/m2 
E)  9.78 × 10-6 N/m2

Question 16

In an electromagnetic wave the   and   fields are oriented such that

Accepted Answer

A)  they are parallel to one another and perpendicular to the direction of wave propagation. 
B)  they are parallel to one another and parallel to the direction of wave propagation. 
C)  they are perpendicular to one another and perpendicular to the direction of wave propagation. 
D)  they are perpendicular to one another and parallel to the direction of wave propagation. 
E)  None of the above answers is correct. 
A)  they are parallel to one another and perpendicular to the direction of wave propagation. 
B)  they are parallel to one another and parallel to the direction of wave propagation. 
C)  they are perpendicular to one another and perpendicular to the direction of wave propagation. 
D)  they are perpendicular to one another and parallel to the direction of wave propagation. 
E)  None of the above answers is correct.

Question 17

An 8.000-mW laser beam emits a cylindrical beam of light 0.6000 mm in diameter. What is the maximum value of the magnetic field?

Accepted Answer

A)  9.240 × 10-6 T 
B)  17.22 × 10-6 T 
C)  12.42 × 10-6 T 
D)  20.50 × 10-6 T 
E)  15.40 × 10-6 T 
A)  9.240 × 10-6 T 
B)  17.22 × 10-6 T 
C)  12.42 × 10-6 T 
D)  20.50 × 10-6 T 
E)  15.40 × 10-6 T

Question 18

A laser beam takes 24 ms to be reflected from the surface of a planet. How far from the laser source is this planet's surface?

Accepted Answer

A)  24 × 105 m 
B)  12 × 105 m 
C)  18 × 105 m 
D)  36 × 105 m 
E)  48 × 105 m 
A)  24 × 105 m 
B)  12 × 105 m 
C)  18 × 105 m 
D)  36 × 105 m 
E)  48 × 105 m

Question 19

The Doppler effect applies to sound waves but not to electromagnetic waves.

Accepted Answer

A) True 
 B)False

Question 20

Unpolarized light of intensity Io passed through a Polaroid sheet with its polarizing axis at the 12 o'clock position and then through a second with its polarizing axis at the 1 o'clock position. What is the intensity of the emerging light?

Accepted Answer

Exam 25: Electromagnetic Waves

The maximum value of the magnetic field component of an electromagnetic wave is 2.81 μT. What is the rms value of the magnetic field?

A 60.0 W light bulb radiates light uniformly in all different directions. What is the value of E at a distance of 0.400 m from the bulb?

The total electromagnetic power emitted by the Sun is 3.8 ×1026 W. What is the radiation pressure near the orbit of Mercury, which has an orbital radius of 5.8 × 1010 m?

How far does a beam of light travel in one full year?

The wavelength of a certain portion of microwaves is 40 mm. What is its frequency?

Electromagnetic waves are a result of a stationary electric field and a changing magnetic field.

A car is going past a radio station at a speed of 40.0 m/s. If the radio station broadcasts at a frequency of 74.5 MHz, what change in frequency does the driver observe?

The electric energy density in an electromagnetic wave is higher than its magnetic energy density.

Which of the following represents the maximum value of the magnetic field at a distance of 2.5 m from a 100 W light bulb?

An electromagnetic wave is propagating towards the west. At a certain moment the direction of the magnetic field vector associated with this wave points vertically up. What is the direction of the electric field vector?

A car is approaching a radio station at a speed of 25.0 m/s. If the radio station broadcasts at a frequency of 74.5 MHz, what change in frequency does the driver observe?

A radio station broadcasts at 80 MHz. How long does it take for this radio signal to travel a distance of 20 × 106 m?

The speed of electromagnetic waves through a vacuum is ten times the speed of sound in air.

The average intensity of the sunlight in Miami, Florida, is 1040 W/m2. What is the average value of the radiation pressure due to this sunlight in Miami?

In an electromagnetic wave the and fields are oriented such that

An 8.000-mW laser beam emits a cylindrical beam of light 0.6000 mm in diameter. What is the maximum value of the magnetic field?

A laser beam takes 24 ms to be reflected from the surface of a planet. How far from the laser source is this planet's surface?

The Doppler effect applies to sound waves but not to electromagnetic waves.

Unpolarized light of intensity Io passed through a Polaroid sheet with its polarizing axis at the 12 o'clock position and then through a second with its polarizing axis at the 1 o'clock position. What is the intensity of the emerging light?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

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The total electromagnetic power emitted by the Sun is 3.8 ×10²⁶ W. What is the radiation pressure near the orbit of Mercury, which has an orbital radius of 5.8 × 10¹⁰ m?

A radio station broadcasts at 80 MHz. How long does it take for this radio signal to travel a distance of 20 × 10⁶ m?

The average intensity of the sunlight in Miami, Florida, is 1040 W/m². What is the average value of the radiation pressure due to this sunlight in Miami?

Unpolarized light of intensity I_o passed through a Polaroid sheet with its polarizing axis at the 12 o'clock position and then through a second with its polarizing axis at the 1 o'clock position. What is the intensity of the emerging light?