Question 1

At every instant the ratio of the magnitude of the electric to the magnetic field in an electromagnetic wave in vacuum is equal to

Accepted Answer

A)  the speed of radio waves. 
B)  the speed of light. 
C)  the speed of gamma rays. 
D)  all of the above. 
E)  only (a) and (b) above. 
A)  the speed of radio waves. 
B)  the speed of light. 
C)  the speed of gamma rays. 
D)  all of the above. 
E)  only (a) and (b) above.

Question 2

The Earth is 1.49 × 1011 meters from the sun. If the solar radiation at the top of the Earth's atmosphere is 1340 W/m2, what is the total power output of the sun?

Accepted Answer

A)  7.10 × 1027 W 
B)  2.20 × 1030 W 
C)  6.62 × 1026 W 
D)  3.74 × 1026 W 
E)  2.98 × 1025 W 
A)  7.10 × 1027 W 
B)  2.20 × 1030 W 
C)  6.62 × 1026 W 
D)  3.74 × 1026 W 
E)  2.98 × 1025 W

Question 3

When E and B are the amplitudes of the electric and magnetic fields in an electromagnetic wave in vacuum, the total average energy density in the wave is

Accepted Answer

A) 
  . 
B) 
  . 
C)  ε0E2. 
D) 
  . 
E) 
  . 
A) 
  . 
B) 
  . 
C)  ε0E2. 
D) 
  . 
E) 
  .

Question 4

Since ε0 = 8.85 × 10−12 C2 / N ⋅ m2, the units of ε0E2 can be reduced to

Accepted Answer

A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  . 
A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  .

Question 5

You can raise the temperature of an object with

Accepted Answer

A)  microwaves. 
B)  infrared waves. 
C)  ultraviolet rays. 
D)  all of the above. 
E)  only (a) and (b) above. 
A)  microwaves. 
B)  infrared waves. 
C)  ultraviolet rays. 
D)  all of the above. 
E)  only (a) and (b) above.

Question 6

Two identical silver spheres of mass m and radius r are placed a distance R (sphere 1) and 2R (sphere 2) from the sun respectively. The ratio of the pressure of solar radiation on sphere 2 to that on sphere 1 is

Accepted Answer

A)  0.25. 
B)  0.50. 
C)  1.0. 
D)  2.0. 
E)  4.0. 
A)  0.25. 
B)  0.50. 
C)  1.0. 
D)  2.0. 
E)  4.0.

Question 7

A plane parallel plate capacitor has plates of 10 cm2 area that are 1.0 mm apart. At an instant when charge is being accumulated on the plates at a rate of 12 nC/s, the displacement current between the plates is

Accepted Answer

A)  1.06 × 10−16 A. 
B)  1.2 × 10−8 A. 
C)  8.85 × 10−9 A. 
D)  1.00 A. 
E)  1.36 A. 
A)  1.06 × 10−16 A. 
B)  1.2 × 10−8 A. 
C)  8.85 × 10−9 A. 
D)  1.00 A. 
E)  1.36 A.

Question 8

In an electromagnetic wave, 1) how are the electric and magnetic field directions related and 2) how is the direction of travel determined from their directions? (   is the velocity of the light wave.)

Accepted Answer

A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  . 
A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  .

Question 9

The magnetic field amplitude in an electromagnetic wave in vacuum is related to the electric field amplitude by B =

Accepted Answer

A) 
  . 
B) 
  . 
C)  E. 
D) 
  . 
E)  cE. 
A) 
  . 
B) 
  . 
C)  E. 
D) 
  . 
E)  cE.

Question 10

A 100-kW radio station emits EM waves in all directions from an antenna on top of a mountain. What is the intensity of the signal at a distance of 10 km?

Accepted Answer

A)  8 × 10−5 W/m2 
B)  8 × 10−6 W/m2 
C)  3 × 10−3 W/m2 
D)  0.8 W/m2 
E)  2.5 × 10−5 W/m2 
A)  8 × 10−5 W/m2 
B)  8 × 10−6 W/m2 
C)  3 × 10−3 W/m2 
D)  0.8 W/m2 
E)  2.5 × 10−5 W/m2

Question 11

Magnetic fields are produced by

Accepted Answer

A)  constant electric currents. 
B)  electric currents that vary sinusoidally with time. 
C)  time-varying electric fields. 
D)  all of the above. 
E)  only (a) and (b) above. 
A)  constant electric currents. 
B)  electric currents that vary sinusoidally with time. 
C)  time-varying electric fields. 
D)  all of the above. 
E)  only (a) and (b) above.

Question 12

An FM radio station broadcasts at 98.6 MHz. What is the wavelength of the radiowaves?

Accepted Answer

A)  60.8 m 
B)  6.08 m 
C)  3.04 m 
D)  0.314 m 
E)  0.33 cm 
A)  60.8 m 
B)  6.08 m 
C)  3.04 m 
D)  0.314 m 
E)  0.33 cm

Question 13

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by   in SI units. What is the speed of the EM wave?

Accepted Answer

A)  3 × 108 m/s 
B)  100 m/s 
C)  106 m/s 
D)  2 × 107 m/s 
E)  2 × 108 m/s 
A)  3 × 108 m/s 
B)  100 m/s 
C)  106 m/s 
D)  2 × 107 m/s 
E)  2 × 108 m/s

Question 14

If the maximum E-component of an electromagnetic wave is 600 V/m, what is the maximum B-component?

Accepted Answer

A)  1.4 T 
B)  1.8 × 10−5 T 
C)  2.0 × 10−6 T 
D)  1.0 × 10−3 T 
E)  1.6 × 10−10 T 
A)  1.4 T 
B)  1.8 × 10−5 T 
C)  2.0 × 10−6 T 
D)  1.0 × 10−3 T 
E)  1.6 × 10−10 T

Question 15

The correct form of Ampere's law for circuits with gaps in them is

Accepted Answer

A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  . 
A) 
  . 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  .

Question 16

Green light has a wavelength of 5.4 × 10−7 m. What is the frequency of this EM-wave in air?

Accepted Answer

A)  5.55 × 1014 Hz 
B)  6.00 × 1011 Hz 
C)  9.00 × 108 Hz 
D)  3.00 × 1010 MHz 
E)  1.80 × 1015 Hz 
A)  5.55 × 1014 Hz 
B)  6.00 × 1011 Hz 
C)  9.00 × 108 Hz 
D)  3.00 × 1010 MHz 
E)  1.80 × 1015 Hz

Question 17

A possible means of spaceflight is to place a perfectly reflecting aluminized sheet into Earth orbit and use the light from the sun to push this solar sail. If a huge sail of area 6.00 × 105 m2 and mass 6000 kg were placed into orbit and turned toward the sun, what would be the force exerted on the sail? (Assume a solar intensity of 1380 W/m2.)

Accepted Answer

Question 18

A spherical particle of density   and 2.00 mm radius is located at the same distance from the Sun as the Earth. RSE = 1.5 × 1011 m.   . If the particle absorbs 100 percent of the sunlight reaching it, the ratio of the force exerted by the solar radiation to the force of gravity exerted on the particle by the Sun is

Accepted Answer

A)  5.8 × 10−5. 
B)  0.58. 
C)  1.0. 
D)  1.7. 
E)  1.7 × 104. 
A)  5.8 × 10−5. 
B)  0.58. 
C)  1.0. 
D)  1.7. 
E)  1.7 × 104.

Question 19

What is the maximum radiation pressure exerted by sunlight in space (S = 1350 W/m2) on a highly polished silver surface?

Accepted Answer

A)  1.4 × 10−2 Pa 
B)  0.12 Pa 
C)  9.0 × 10−6 Pa 
D)  4.5 × 10−5 Pa 
E)  2.3 × 10−6 Pa 
A)  1.4 × 10−2 Pa 
B)  0.12 Pa 
C)  9.0 × 10−6 Pa 
D)  4.5 × 10−5 Pa 
E)  2.3 × 10−6 Pa

Question 20

High frequency alternating current is passed through a solenoid that contains a solid copper core insulated from the coils of the solenoid. Which statement is correct?

Accepted Answer

A)  A copper core remains cool no matter what the frequency of the current in the solenoid is. 
B)  The copper core remains cool because the induced emf is parallel to the solenoid axis and fluctuates rapidly. 
C)  The copper core heats up because an emf parallel to the solenoid axis is induced in the core. 
D)  The copper core heats up because circular currents around its axis are induced in the core. 
E)  The copper core heats up because the electric field induced in the copper is parallel to the magnetic field produced by the solenoid. 
A)  A copper core remains cool no matter what the frequency of the current in the solenoid is. 
B)  The copper core remains cool because the induced emf is parallel to the solenoid axis and fluctuates rapidly. 
C)  The copper core heats up because an emf parallel to the solenoid axis is induced in the core. 
D)  The copper core heats up because circular currents around its axis are induced in the core. 
E)  The copper core heats up because the electric field induced in the copper is parallel to the magnetic field produced by the solenoid.

Exam 34: Electromagnetic Waves

At every instant the ratio of the magnitude of the electric to the magnetic field in an electromagnetic wave in vacuum is equal to

The Earth is 1.49 × 1011 meters from the sun. If the solar radiation at the top of the Earth's atmosphere is 1340 W/m2, what is the total power output of the sun?

When E and B are the amplitudes of the electric and magnetic fields in an electromagnetic wave in vacuum, the total average energy density in the wave is

Since ε0 = 8.85 × 10−12 C2 / N ⋅ m2, the units of ε0E2 can be reduced to

You can raise the temperature of an object with

Two identical silver spheres of mass m and radius r are placed a distance R (sphere 1) and 2R (sphere 2) from the sun respectively. The ratio of the pressure of solar radiation on sphere 2 to that on sphere 1 is

A plane parallel plate capacitor has plates of 10 cm2 area that are 1.0 mm apart. At an instant when charge is being accumulated on the plates at a rate of 12 nC/s, the displacement current between the plates is

In an electromagnetic wave, 1) how are the electric and magnetic field directions related and 2) how is the direction of travel determined from their directions? ( is the velocity of the light wave.)

The magnetic field amplitude in an electromagnetic wave in vacuum is related to the electric field amplitude by B =

A 100-kW radio station emits EM waves in all directions from an antenna on top of a mountain. What is the intensity of the signal at a distance of 10 km?

Magnetic fields are produced by

An FM radio station broadcasts at 98.6 MHz. What is the wavelength of the radiowaves?

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by in SI units. What is the speed of the EM wave?

If the maximum E-component of an electromagnetic wave is 600 V/m, what is the maximum B-component?

The correct form of Ampere's law for circuits with gaps in them is

Green light has a wavelength of 5.4 × 10−7 m. What is the frequency of this EM-wave in air?

What is the maximum radiation pressure exerted by sunlight in space (S = 1350 W/m2) on a highly polished silver surface?

High frequency alternating current is passed through a solenoid that contains a solid copper core insulated from the coils of the solenoid. Which statement is correct?

Physics and Measurement

Motion in One Dimension

Vectors

Motion in Two Dimensions

The Laws of Motion

Circular Motion and Other Applications of Newtons Laws

Energy of a System

Conservation of Energy

Linear Momentum and Collisions

Rotation of a Rigid Object About a Fixed Axis

Angular Momentum

Static Equilibrium and Elasticity

Universal Gravitation

Fluid Mechanics

Oscillatory Motion

Wave Motion

Superposition and Standing Waves

Temperature

The First Law of Thermodynamics

The Kinetic Theory of Gases

Heat Engines, Entropy, and the Second Law of Thermodynamics

Electric Fields

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current and Resistance

Direct-Current Circuits

Magnetic Fields

Sources of the Magnetic Field

Faradays Law

Inductance

Alternating-Current Circuits

The Nature of Light and the Principles of Ray Optics

Image Formation

Wave Optics

Diffraction Patterns and Polarization

Relativity

Introduction to Quantum Physics

Quantum Mechanics

Atomic Physics

Molecules and Solids

Nuclear Structure

Particle Physics and Cosmology

Filters

The Earth is 1.49 × 10¹¹ meters from the sun. If the solar radiation at the top of the Earth's atmosphere is 1340 W/m², what is the total power output of the sun?

Since ε₀ = 8.85 × 10−¹² C² / N ⋅ m², the units of ε₀E² can be reduced to

A plane parallel plate capacitor has plates of 10 cm² area that are 1.0 mm apart. At an instant when charge is being accumulated on the plates at a rate of 12 nC/s, the displacement current between the plates is

Green light has a wavelength of 5.4 × 10−⁷ m. What is the frequency of this EM-wave in air?

What is the maximum radiation pressure exerted by sunlight in space (S = 1350 W/m²) on a highly polished silver surface?