Question 1

For electromagnetic radiation of intensity of 1.00 W/m2, what is the rms value of the electric field?

Accepted Answer

A)  19.4 V/m 
B)  9.69 V/m 
C)  6.45 × 10-8 V/m 
D)  9.11 × 10-8 V/m 
E)  3.00 × 107 V/m 
A)  19.4 V/m 
B)  9.69 V/m 
C)  6.45 × 10-8 V/m 
D)  9.11 × 10-8 V/m 
E)  3.00 × 107 V/m

Question 2

Using the approximate formula for the Doppler shift, fo ≈ fs (1 + vrel/c) one finds that a source is moving away at 0.60 c. What result would the exact formula yield for the recession speed?

Accepted Answer

A)  0.84 c 
B)  0.72 c 
C)  0.60 c 
D)  0.54 c 
E)  0.40 c 
A)  0.84 c 
B)  0.72 c 
C)  0.60 c 
D)  0.54 c 
E)  0.40 c

Question 3

How long does it take for a radio signal to travel to a spacecraft 1.5 × 1011 m away?

Accepted Answer

A)  5.0 s 
B)  50 s 
C)  5.0 × 102 s 
D)  5.0 × 103 s 
E)  1.0 × 103 s 
A)  5.0 s 
B)  50 s 
C)  5.0 × 102 s 
D)  5.0 × 103 s 
E)  1.0 × 103 s

Question 4

At the Earth's orbital distance from the Sun, the intensity of solar radiation is approximately 1400 W/m2. What is the intensity at Mercury's orbital distance, which is 38.7% that of Earth?

Accepted Answer

A)  2280 W/m2 
B)  3800 W/m2 
C)  9300 W/m2 
D)  540 W/m2 
A)  2280 W/m2 
B)  3800 W/m2 
C)  9300 W/m2 
D)  540 W/m2

Question 5

In what spectral range are black lights that cause materials to fluoresce in the visible?

Accepted Answer

A)  x-ray 
B)  infrared 
C)  ultraviolet 
D)  radio 
E)  microwave 
A)  x-ray 
B)  infrared 
C)  ultraviolet 
D)  radio 
E)  microwave

Question 6

The longest wavelengths of visible light are in the color

Accepted Answer

A)  red. 
B)  orange. 
C)  green. 
D)  blue. 
E)  violet. 
A)  red. 
B)  orange. 
C)  green. 
D)  blue. 
E)  violet.

Question 7

The electromagnetic spectrum arranged by increasing wavelength is

Accepted Answer

A)  radio waves, gamma rays, x-rays, visible light, infrared, microwave, ultraviolet. 
B)  x-rays, gamma rays, ultraviolet, visible light, infrared, microwave, radio waves. 
C)  infrared, gamma rays, x-rays, ultraviolet, visible light, microwave, radio waves. 
D)  gamma rays, x-rays, ultraviolet, visible light, infrared, microwave, radio waves. 
A)  radio waves, gamma rays, x-rays, visible light, infrared, microwave, ultraviolet. 
B)  x-rays, gamma rays, ultraviolet, visible light, infrared, microwave, radio waves. 
C)  infrared, gamma rays, x-rays, ultraviolet, visible light, microwave, radio waves. 
D)  gamma rays, x-rays, ultraviolet, visible light, infrared, microwave, radio waves.

Question 8

A distant star emits light of wavelength 620 nm. As measured by an Earth observer, the light is shifted to 635 nm. Assuming the star is moving either away (positive radial velocity) or toward (negative radial velocity) Earth, what is its radial velocity relative to Earth?

Accepted Answer

A)  −0.11c 
B)  −0.024c 
C)  0.11c 
D)  0.024c 
A)  −0.11c 
B)  −0.024c 
C)  0.11c 
D)  0.024c

Question 9

A 20 W laser beam, with an initial diameter of 2.0 mm, spreads out to a diameter of 2.0 m after traveling 10,000 m. What is the initial Erms of the beam?

Accepted Answer

A)  4.9 × 104 V/m 
B)  2.5 × 103 V/m 
C)  1.2 × 103 V/m 
D)  1.9 × 102 V/m 
E)  1.7 × 102 V/m 
A)  4.9 × 104 V/m 
B)  2.5 × 103 V/m 
C)  1.2 × 103 V/m 
D)  1.9 × 102 V/m 
E)  1.7 × 102 V/m

Question 10

Which of the following is the direction of an electromagnetic wave having electric and magnetic field vectors E and B?

Accepted Answer

A)  E 
B)  B 
C)  E + B 
D)  E × B 
E)  B × E 
A)  E 
B)  B 
C)  E + B 
D)  E × B 
E)  B × E

Question 11

Plane-polarized light of intensity I0 is sent through two polarizers, the first of which is rotated 45° clockwise relative to the original polarization, while the second is rotated 45° counterclockwise relative to the original polarization. What is the transmitted intensity?

Accepted Answer

A)  0.71 I0 
B)  0.50 I0 
C)  0.35 I0 
D)  0.25 I0 
E)  0 
A)  0.71 I0 
B)  0.50 I0 
C)  0.35 I0 
D)  0.25 I0 
E)  0

Question 12

If the intensity of radiation from the Sun is 1.4 kW/m2 at a distance of 150 × 106 km, at what distance is the intensity 5.6 kW/m2?

Accepted Answer

A)  300 × 106 km 
B)  100 × 106 km 
C)  75 × 106 km 
D)  38 × 106 km 
E)  less than 30 × 106 km 
A)  300 × 106 km 
B)  100 × 106 km 
C)  75 × 106 km 
D)  38 × 106 km 
E)  less than 30 × 106 km

Question 13

A distant star emits light with a peak intensity at 620 nm. If the star is moving toward Earth at 0.024c, what is the wavelength of the peak intensity as measured by an Earth observer?

Accepted Answer

A)  605 nm 
B)  591 nm 
C)  650 nm 
D)  635 nm 
A)  605 nm 
B)  591 nm 
C)  650 nm 
D)  635 nm

Question 14

Light of wavelength 600 nm in air enters a medium in which the index of refraction is 1.73. What is the frequency of this light in the medium?

Accepted Answer

A)  5.00 × 1014 Hz 
B)  2.89 × 1014 Hz 
C)  8.65 × 1014 Hz 
D)  3.46 × 1014 Hz 
E)  1.04 × 1014 Hz 
A)  5.00 × 1014 Hz 
B)  2.89 × 1014 Hz 
C)  8.65 × 1014 Hz 
D)  3.46 × 1014 Hz 
E)  1.04 × 1014 Hz

Question 15

What index of refraction halves the wavelength that light has in a vacuum?

Accepted Answer

A)  1.33 
B)  1.50 
C)  1.41 
D)  2.00 
E)  5.00 
A)  1.33 
B)  1.50 
C)  1.41 
D)  2.00 
E)  5.00

Question 16

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 the wavelength of the wave?

Accepted Answer

A)  5.00 m 
B)  0.200 m 
C)  1.26 m 
D)  2.52 m 
E)  0.796 m 
A)  5.00 m 
B)  0.200 m 
C)  1.26 m 
D)  2.52 m 
E)  0.796 m

Question 17

Wavelengths just shorter than visible light are classified as

Accepted Answer

A)  gamma rays. 
B)  x-rays. 
C)  microwaves. 
D)  ultraviolet. 
E)  radio waves. 
A)  gamma rays. 
B)  x-rays. 
C)  microwaves. 
D)  ultraviolet. 
E)  radio waves.

Question 18

εo μo = ?

Accepted Answer

A)  c 
B)  c2 
C)  c−1 
D)  c−2 
E)  c½ 
A)  c 
B)  c2 
C)  c−1 
D)  c−2 
E)  c½

Question 19

The Sun is 1.50 × 108 km from the Earth. How long does it take for light to reach us from the Sun?

Accepted Answer

A)  2.00 ms 
B)  2.00 s 
C)  0.50 s 
D)  8.33 min 
E)  almost instantaneous 
A)  2.00 ms 
B)  2.00 s 
C)  0.50 s 
D)  8.33 min 
E)  almost instantaneous

Question 20

At the Earth's orbital distance from the Sun, the intensity of solar radiation is approximately 1400 W/m2. What is the rms electric field?

Accepted Answer

A)  726 V/m 
B)  363 kV/m 
C)  527 kV/m 
D)  513 kV/m 
A)  726 V/m 
B)  363 kV/m 
C)  527 kV/m 
D)  513 kV/m

Exam 22: Electromagnetic Waves

For electromagnetic radiation of intensity of 1.00 W/m2, what is the rms value of the electric field?

Using the approximate formula for the Doppler shift, fo ≈ fs (1 + vrel/c) one finds that a source is moving away at 0.60 c. What result would the exact formula yield for the recession speed?

How long does it take for a radio signal to travel to a spacecraft 1.5 × 1011 m away?

At the Earth's orbital distance from the Sun, the intensity of solar radiation is approximately 1400 W/m2. What is the intensity at Mercury's orbital distance, which is 38.7% that of Earth?

In what spectral range are black lights that cause materials to fluoresce in the visible?

The longest wavelengths of visible light are in the color

The electromagnetic spectrum arranged by increasing wavelength is

A distant star emits light of wavelength 620 nm. As measured by an Earth observer, the light is shifted to 635 nm. Assuming the star is moving either away (positive radial velocity) or toward (negative radial velocity) Earth, what is its radial velocity relative to Earth?

A 20 W laser beam, with an initial diameter of 2.0 mm, spreads out to a diameter of 2.0 m after traveling 10,000 m. What is the initial Erms of the beam?

Which of the following is the direction of an electromagnetic wave having electric and magnetic field vectors E and B?

Plane-polarized light of intensity I0 is sent through two polarizers, the first of which is rotated 45° clockwise relative to the original polarization, while the second is rotated 45° counterclockwise relative to the original polarization. What is the transmitted intensity?

If the intensity of radiation from the Sun is 1.4 kW/m2 at a distance of 150 × 106 km, at what distance is the intensity 5.6 kW/m2?

A distant star emits light with a peak intensity at 620 nm. If the star is moving toward Earth at 0.024c, what is the wavelength of the peak intensity as measured by an Earth observer?

Light of wavelength 600 nm in air enters a medium in which the index of refraction is 1.73. What is the frequency of this light in the medium?

What index of refraction halves the wavelength that light has in a vacuum?

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 the wavelength of the wave?

Wavelengths just shorter than visible light are classified as

εo μo = ?

The Sun is 1.50 × 108 km from the Earth. How long does it take for light to reach us from the Sun?

At the Earth's orbital distance from the Sun, the intensity of solar radiation is approximately 1400 W/m2. What is the rms electric field?

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

For electromagnetic radiation of intensity of 1.00 W/m², what is the rms value of the electric field?

Using the approximate formula for the Doppler shift, f_o ≈ f_s (1 + v_rel/c) one finds that a source is moving away at 0.60 c. What result would the exact formula yield for the recession speed?

How long does it take for a radio signal to travel to a spacecraft 1.5 × 10¹¹ m away?

At the Earth's orbital distance from the Sun, the intensity of solar radiation is approximately 1400 W/m². What is the intensity at Mercury's orbital distance, which is 38.7% that of Earth?

A 20 W laser beam, with an initial diameter of 2.0 mm, spreads out to a diameter of 2.0 m after traveling 10,000 m. What is the initial E_rms of the beam?

Plane-polarized light of intensity I₀ is sent through two polarizers, the first of which is rotated 45° clockwise relative to the original polarization, while the second is rotated 45° counterclockwise relative to the original polarization. What is the transmitted intensity?

If the intensity of radiation from the Sun is 1.4 kW/m² at a distance of 150 × 10⁶ km, at what distance is the intensity 5.6 kW/m²?

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 the wavelength of the wave?

ε_o μ_o = ?

The Sun is 1.50 × 10⁸ km from the Earth. How long does it take for light to reach us from the Sun?