Question 1

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

Accepted Answer

A)  500 MHz 
B)  250 kHz 
C)  1.25 MHz 
D)  10 mHz 
E)  300 MHz 
A)  500 MHz 
B)  250 kHz 
C)  1.25 MHz 
D)  10 mHz 
E)  300 MHz C

Question 2

What should be the height of a dipole antenna (of dimensions 1/4 wavelength) if it is to transmit 1200 kHz radiowaves?

Accepted Answer

A)  11.4 m 
B)  60 cm 
C)  1.12 m 
D)  62.5 m 
E)  250 m 
A)  11.4 m 
B)  60 cm 
C)  1.12 m 
D)  62.5 m 
E)  250 m D

Question 3

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

Accepted Answer

A)  1000 V/m 
B)  180 V/m 
C)  81 V/m 
D)  360 V/m 
E)  0.40 V/m 
A)  1000 V/m 
B)  180 V/m 
C)  81 V/m 
D)  360 V/m 
E)  0.40 V/m D

Question 4

At a distance of 10 km from a radio transmitter, the amplitude of the E-field is 0.20 volts/meter. What is the total power emitted by the radio transmitter?

Accepted Answer

A)  10 kW 
B)  67 kW 
C)  140 kW 
D)  245 kW 
E)  21 kW 
A)  10 kW 
B)  67 kW 
C)  140 kW 
D)  245 kW 
E)  21 kW

Question 5

The sun radiates energy at a rate of 3.86 × 1026 W. Its radius is 7.0 × 108 m. If the distance from the Earth to the sun is 1.5 × 1011 m, what is the intensity of solar radiation at the top of the Earth's atmosphere?

Accepted Answer

Question 6

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by   in SI units. Find the average power per square meter carried by the EM wave.

Accepted Answer

A)  720 W 
B)  172 W 
C)  500 W 
D)  2 × 107 W 
E)  86 W 
A)  720 W 
B)  172 W 
C)  500 W 
D)  2 × 107 W 
E)  86 W

Question 7

Find the force exerted by reflecting sunlight off a reflecting aluminum sheet in space if the area normal to the sunlight is 10000 m2 and the solar intensity is 1350 W/m2.

Accepted Answer

A)  0.72 N 
B)  0.09 N 
C)  9 N 
D)  45 N 
E)  0.18 N 
A)  0.72 N 
B)  0.09 N 
C)  9 N 
D)  45 N 
E)  0.18 N

Question 8

The intensity of radiation reaching the earth from the sun is 1 350 W/m2. The earth's radius is 6.4 × 106 m. How big a force does this radiation exert on the earth? (Assume it is all absorbed.)

Accepted Answer

A)  5.8 × 108 N 
B)  1.2 × 109 N 
C)  2.3 × 109 N 
D)  4.6 × 109 N 
E)  1.7 × 1017 N 
A)  5.8 × 108 N 
B)  1.2 × 109 N 
C)  2.3 × 109 N 
D)  4.6 × 109 N 
E)  1.7 × 1017 N

Question 9

How much electromagnetic energy is contained in each cubic meter near the Earth's surface if the intensity of sunlight under clear skies is 1000 W/m2?

Accepted Answer

A)  3.3 × 10−6 J 
B)  3.3 J 
C)  0.003 J 
D)  10−4 J 
E)  3.0 × 105 J 
A)  3.3 × 10−6 J 
B)  3.3 J 
C)  0.003 J 
D)  10−4 J 
E)  3.0 × 105 J

Question 10

If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m2, calculate the peak values of E and B.

Accepted Answer

A)  300 V/m, 10−4 T 
B)  1 000 V/m, 3.35 × 10−6 T 
C)  225 V/m, 1.60× 10−3 T 
D)  111 V/m, 3.00 × 10−5 T 
E)  711 V/m, 2.37 × 10−6 T 
A)  300 V/m, 10−4 T 
B)  1 000 V/m, 3.35 × 10−6 T 
C)  225 V/m, 1.60× 10−3 T 
D)  111 V/m, 3.00 × 10−5 T 
E)  711 V/m, 2.37 × 10−6 T

Question 11

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

Accepted Answer

A)  120 m 
B)  240 m 
C)  60 m 
D)  100 m 
E)  360 m 
A)  120 m 
B)  240 m 
C)  60 m 
D)  100 m 
E)  360 m

Question 12

The speed of light is given by the value of

Accepted Answer

A)  ε0μ0. 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  . 
A)  ε0μ0. 
B) 
  . 
C) 
  . 
D) 
  . 
E) 
  .

Question 13

What is the average value of the magnitude of the Poynting vector   at 1 meter from a 100-watt lightbulb radiating in all directions?

Accepted Answer

A)  1 W/m2 
B)  4 W/m2 
C)  2 W/m2 
D)  8 W/m2 
E)  12 W/m2 
A)  1 W/m2 
B)  4 W/m2 
C)  2 W/m2 
D)  8 W/m2 
E)  12 W/m2

Question 14

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

Accepted Answer

A)  2.25 × 10−5 Pa 
B)  0.06 Pa 
C)  7 × 10−4 Pa 
D)  4.5 × 10−6 Pa 
E)  9.0 × 10−6 Pa 
A)  2.25 × 10−5 Pa 
B)  0.06 Pa 
C)  7 × 10−4 Pa 
D)  4.5 × 10−6 Pa 
E)  9.0 × 10−6 Pa

Question 15

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 gravitational force exerted by the sun on sphere 1 to the pressure of solar radiation on sphere 1 is T1; the ratio for sphere 2 is T2. The ratio of T2 to T1 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 16

Find the frequency of X-rays of wavelength 1 Å = 10−10 m.

Accepted Answer

A)  3 × 1018 Hz 
B)  3 × 1010 MHz 
C)  6 × 109 Hz 
D)  3 × 108 Hz 
E)  3 × 1020 Hz 
A)  3 × 1018 Hz 
B)  3 × 1010 MHz 
C)  6 × 109 Hz 
D)  3 × 108 Hz 
E)  3 × 1020 Hz

Question 17

Near the surface of the planet, the Earth's magnetic field is about 0.50 × 10−4 T. How much energy is stored in 1.0 m3 of the atmosphere because of this field?

Accepted Answer

Question 18

In the atmosphere, the shortest wavelength electromagnetic waves are called

Accepted Answer

A)  microwaves. 
B)  infrared waves. 
C)  ultraviolet waves. 
D)  X-rays. 
E)  gamma rays. 
A)  microwaves. 
B)  infrared waves. 
C)  ultraviolet waves. 
D)  X-rays. 
E)  gamma rays.

Question 19

An open circuit consists of a 12 μF parallel plate capacitor charged to 200 V and a 10 Ω resistor. At the instant when a switch closes the circuit (with no battery in it) the displacement current between the plates of the capacitor is

Accepted Answer

A)  1.2 μA. 
B)  2.4 × 10−4 A. 
C)  2.4 mA. 
D)  10 A. 
E)  20 A. 
A)  1.2 μA. 
B)  2.4 × 10−4 A. 
C)  2.4 mA. 
D)  10 A. 
E)  20 A.

Question 20

A solar cell has a light-gathering area of 10 cm2 and produces 0.2 A at 0.8 V (DC) when illuminated with S = 1 000 W/m2 sunlight. What is the efficiency of the solar cell?

Accepted Answer

A)  16% 
B)  7% 
C)  23% 
D)  4% 
E)  32% 
A)  16% 
B)  7% 
C)  23% 
D)  4% 
E)  32%

Exam 34: Electromagnetic Waves

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

What should be the height of a dipole antenna (of dimensions 1/4 wavelength) if it is to transmit 1200 kHz radiowaves?

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

At a distance of 10 km from a radio transmitter, the amplitude of the E-field is 0.20 volts/meter. What is the total power emitted by the radio transmitter?

The sun radiates energy at a rate of 3.86 × 1026 W. Its radius is 7.0 × 108 m. If the distance from the Earth to the sun is 1.5 × 1011 m, what is the intensity of solar radiation at the top of the Earth's atmosphere?

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by in SI units. Find the average power per square meter carried by the EM wave.

Find the force exerted by reflecting sunlight off a reflecting aluminum sheet in space if the area normal to the sunlight is 10000 m2 and the solar intensity is 1350 W/m2.

The intensity of radiation reaching the earth from the sun is 1 350 W/m2. The earth's radius is 6.4 × 106 m. How big a force does this radiation exert on the earth? (Assume it is all absorbed.)

How much electromagnetic energy is contained in each cubic meter near the Earth's surface if the intensity of sunlight under clear skies is 1000 W/m2?

If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m2, calculate the peak values of E and B.

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

The speed of light is given by the value of

What is the average value of the magnitude of the Poynting vector at 1 meter from a 100-watt lightbulb radiating in all directions?

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

Find the frequency of X-rays of wavelength 1 Å = 10−10 m.

Near the surface of the planet, the Earth's magnetic field is about 0.50 × 10−4 T. How much energy is stored in 1.0 m3 of the atmosphere because of this field?

In the atmosphere, the shortest wavelength electromagnetic waves are called

An open circuit consists of a 12 μF parallel plate capacitor charged to 200 V and a 10 Ω resistor. At the instant when a switch closes the circuit (with no battery in it) the displacement current between the plates of the capacitor is

A solar cell has a light-gathering area of 10 cm2 and produces 0.2 A at 0.8 V (DC) when illuminated with S = 1 000 W/m2 sunlight. What is the efficiency of the solar cell?

Physics and Measurement

Motion in One Dimension

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The Laws of Motion

Circular Motion and Other Applications of Newtons Laws

Energy of a System

Conservation of Energy

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Rotation of a Rigid Object About a Fixed Axis

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Static Equilibrium and Elasticity

Universal Gravitation

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Wave Motion

Superposition and Standing Waves

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The Kinetic Theory of Gases

Heat Engines, Entropy, and the Second Law of Thermodynamics

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Gausss Law

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Current and Resistance

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Sources of the Magnetic Field

Faradays Law

Inductance

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The Nature of Light and the Principles of Ray Optics

Image Formation

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Diffraction Patterns and Polarization

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Introduction to Quantum Physics

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The sun radiates energy at a rate of 3.86 × 10²⁶ W. Its radius is 7.0 × 10⁸ m. If the distance from the Earth to the sun is 1.5 × 10¹¹ m, what is the intensity of solar radiation at the top of the Earth's atmosphere?

Find the force exerted by reflecting sunlight off a reflecting aluminum sheet in space if the area normal to the sunlight is 10000 m² and the solar intensity is 1350 W/m².

The intensity of radiation reaching the earth from the sun is 1 350 W/m². The earth's radius is 6.4 × 10⁶ m. How big a force does this radiation exert on the earth? (Assume it is all absorbed.)

How much electromagnetic energy is contained in each cubic meter near the Earth's surface if the intensity of sunlight under clear skies is 1000 W/m²?

If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m², calculate the peak values of E and B.

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

Find the frequency of X-rays of wavelength 1 Å = 10−¹⁰ m.

Near the surface of the planet, the Earth's magnetic field is about 0.50 × 10−⁴ T. How much energy is stored in 1.0 m³ of the atmosphere because of this field?

A solar cell has a light-gathering area of 10 cm² and produces 0.2 A at 0.8 V (DC) when illuminated with S = 1 000 W/m² sunlight. What is the efficiency of the solar cell?