Question 1

The average electric energy density of an electromagnetic wave is 0.600 × 10-7 J/m3. What is the electric field component of this wave?

Accepted Answer

A)  116 J/Cm 
B)  116 N/C 
C)  116 V/m 
D)  All of the answers given are correct. 
E)  None of the answers given is correct. 
A)  116 J/Cm 
B)  116 N/C 
C)  116 V/m 
D)  All of the answers given are correct. 
E)  None of the answers given is correct.

Question 2

A 60.0-W light bulb radiates light uniformly in all different directions. What is the value of B at a distance of 0.700 m from the bulb?

Accepted Answer

A)  1.76 × 10-7 T 
B)  2.02 × 10-7 T 
C)  2.22 × 10-7 T 
D)  4.86 × 10-7 T 
E)  None of the other answers is correct. 
A)  1.76 × 10-7 T 
B)  2.02 × 10-7 T 
C)  2.22 × 10-7 T 
D)  4.86 × 10-7 T 
E)  None of the other answers is correct.

Question 3

Object A in the shape of a disk of radius r is placed a distance R away from an intense light source. Object B, made from the same material as object A, is in the shape of a disk of radius 2r and placed a distance 2R away from the same light source. We observe which of the following?

Accepted Answer

A)  Both objects experience the same amount of radiation pressure but receive different amounts of linear momentum. 
B)  The objects experience different amounts of radiation pressure and receive different amounts of linear momentum. 
C)  Both objects experience the same amount of radiation pressure and the same amount of linear momentum. 
D)  The objects experience different amounts of radiation pressure but receive the same amount of linear momentum. 
A)  Both objects experience the same amount of radiation pressure but receive different amounts of linear momentum. 
B)  The objects experience different amounts of radiation pressure and receive different amounts of linear momentum. 
C)  Both objects experience the same amount of radiation pressure and the same amount of linear momentum. 
D)  The objects experience different amounts of radiation pressure but receive the same amount of linear momentum.

Question 4

Which one of the following is the correct representation of the electromagnetic waves from longer wavelength to shorter wavelength?

Accepted Answer

A)  radio waves, infrared, microwaves, UV, visible, X-rays, gamma rays 
B)  radio waves, UV, X-rays, microwaves, infrared, visible, gamma rays 
C)  radio waves, microwaves, visible, X-rays, infrared, UV, gamma rays 
D)  radio waves, microwaves, infrared, visible, UV, X-rays, gamma rays 
E)  radio waves, infrared, X-rays, microwaves, UV, visible, gamma rays 
A)  radio waves, infrared, microwaves, UV, visible, X-rays, gamma rays 
B)  radio waves, UV, X-rays, microwaves, infrared, visible, gamma rays 
C)  radio waves, microwaves, visible, X-rays, infrared, UV, gamma rays 
D)  radio waves, microwaves, infrared, visible, UV, X-rays, gamma rays 
E)  radio waves, infrared, X-rays, microwaves, UV, visible, gamma rays

Question 5

In Fizeau's experiment to measure the speed of light, the wheel has 475 notches and rotates with a speed of 55.0 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 8800 m, how much time does it take the wheel to rotate from one notch to the next?

Accepted Answer

A)  11.9 s 
B)  24.8 s 
C)  3.83 × 10-5 s 
D)  7.44 × 10-5 s 
E)  8.44 × 10-5 s 
A)  11.9 s 
B)  24.8 s 
C)  3.83 × 10-5 s 
D)  7.44 × 10-5 s 
E)  8.44 × 10-5 s

Question 6

A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest frequency associated with this portion of the spectrum?

Accepted Answer

A)  1.50 × 1014 Hz 
B)  7.50 × 1013 Hz 
C)  7.50 × 1014 Hz 
D)  7.50 × 1015 Hz 
E)  1.50 × 1015 Hz 
A)  1.50 × 1014 Hz 
B)  7.50 × 1013 Hz 
C)  7.50 × 1014 Hz 
D)  7.50 × 1015 Hz 
E)  1.50 × 1015 Hz

Question 7

Which one of the following is the correct representation of the relationship between the speed of a wave (v), frequency of the wave (f), and its wavelength (λ)?

Accepted Answer

A)  v = 2λ 
B)  v = 2f 
C)  v = λ/f 
D)  v = fλ 
E)  v = f/λ 
A)  v = 2λ 
B)  v = 2f 
C)  v = λ/f 
D)  v = fλ 
E)  v = f/λ

Question 8

In 1676 Romer announced what value for the speed of light?

Accepted Answer

A)  2.55 × 108 m/s 
B)  2.99 × 108 m/s 
C)  1.99 × 108 m/s 
D)  3.13 × 108 m/s 
E)  2.25 × 108 m/s 
A)  2.55 × 108 m/s 
B)  2.99 × 108 m/s 
C)  1.99 × 108 m/s 
D)  3.13 × 108 m/s 
E)  2.25 × 108 m/s

Question 9

A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the lowest frequency associated with this portion of the spectrum?

Accepted Answer

A)  1.50 × 1014 Hz 
B)  7.50 × 1013 Hz 
C)  7.50 × 1014 Hz 
D)  7.50 × 1015 Hz 
E)  1.50 × 1015 Hz 
A)  1.50 × 1014 Hz 
B)  7.50 × 1013 Hz 
C)  7.50 × 1014 Hz 
D)  7.50 × 1015 Hz 
E)  1.50 × 1015 Hz

Question 10

A vertically polarized beam of light of intensity 100 W/m2 passes through two polarizers. The first polarizer is making an angle of 20° with its transmission axis and the second one is making an angle of 40° with its transmission axis. What is the transmitted intensity of this beam of light?

Accepted Answer

A)  22.2 W/m2 
B)  44.4 W/m2 
C)  66.6 W/m2 
D)  78.0 W/m2 
E)  11.7 W/m2 
A)  22.2 W/m2 
B)  44.4 W/m2 
C)  66.6 W/m2 
D)  78.0 W/m2 
E)  11.7 W/m2

Question 11

The frequency of a microwave signal is 9.76 GHz. What is its wavelength in meters?

Accepted Answer

A)  3.07 × 10-2 m 
B)  2.07 × 10-2 m 
C)  1.07 × 10-2 m 
D)  5.07 × 10-2 m 
E)  4.07 × 10-2 m 
A)  3.07 × 10-2 m 
B)  2.07 × 10-2 m 
C)  1.07 × 10-2 m 
D)  5.07 × 10-2 m 
E)  4.07 × 10-2 m

Question 12

The rms value of the electric field component of an electromagnetic wave is 27.2 N/C. What is the maximum value of the electric field?

Accepted Answer

A)  38.5 N/C 
B)  19.2 N/C 
C)  27.2 N/C 
D)  47.4 N/C 
E)  52.8 N/C 
A)  38.5 N/C 
B)  19.2 N/C 
C)  27.2 N/C 
D)  47.4 N/C 
E)  52.8 N/C

Question 13

An electromagnetic wave is a result of electric and magnetic fields acting together.

Accepted Answer

A) True 
 B)False

Question 14

The energy density of an electromagnetic wave is

Accepted Answer

A)  entirely in the electric field. 
B)  entirely in the magnetic field. 
C)  1/4 in the electric field and 3/4 in the magnetic field. 
D)  1/4 in the magnetic field and 3/4 in the electric field. 
E)  equally divided between the magnetic and the electric fields. 
A)  entirely in the electric field. 
B)  entirely in the magnetic field. 
C)  1/4 in the electric field and 3/4 in the magnetic field. 
D)  1/4 in the magnetic field and 3/4 in the electric field. 
E)  equally divided between the magnetic and the electric fields.

Question 15

The first scientific attempt to measure the speed of light was made by

Accepted Answer

A)  Galileo. 
B)  Faraday. 
C)  Maxwell. 
D)  Newton. 
E)  Romer. 
A)  Galileo. 
B)  Faraday. 
C)  Maxwell. 
D)  Newton. 
E)  Romer.

Question 16

The magnetic field component of the electromagnetic wave is 15.0 μT. What is the magnetic energy density of the wave?

Accepted Answer

A)  2.26 × 10-4 J/m3 
B)  8.95 × 10-5 J/m2 
C)  1.79 × 10-4 J/m3 
D)  4.47 × 10-4 J/m2 
E)  9.72 × 10-5 J/m3 
A)  2.26 × 10-4 J/m3 
B)  8.95 × 10-5 J/m2 
C)  1.79 × 10-4 J/m3 
D)  4.47 × 10-4 J/m2 
E)  9.72 × 10-5 J/m3

Question 17

Unpolarized light of intensity I passes through four Polaroid sheets whose polarizing angles are rotated 30° from each other so that the last sheet is aligned at 90° to the first. What is the intensity of the light emerging from the fourth sheet?

Accepted Answer

The answer of Unpolarized light of intensity I passes through...

Question 18

A radio station broadcasts at a frequency of 80 MHz. How far will this signal travel in 67 ms?

Accepted Answer

A)  60 × 106 m 
B)  67 m 
C)  40 × 106 m 
D)  80 m 
E)  20 × 106 m 
A)  60 × 106 m 
B)  67 m 
C)  40 × 106 m 
D)  80 m 
E)  20 × 106 m

Question 19

A Doppler weather radar operates at a frequency of 3.40 GHz. The wave from this radar system reflects from an approaching weather system moving with a speed of 39.0 m/s. What is the difference in frequency between the outgoing and returning waves?

Accepted Answer

A)  442 Hz 
B)  351 Hz 
C)  419 Hz 
D)  322 Hz 
E)  670 Hz 
A)  442 Hz 
B)  351 Hz 
C)  419 Hz 
D)  322 Hz 
E)  670 Hz

Question 20

The value of the magnetic field for a certain type of electromagnetic wave is 2.12 μT. What is the value of the electric field for that wave?

Accepted Answer

A)  636 V/m 
B)  636 N/C 
C)  636 J/Cm 
D)  All of the answers given are correct. 
E)  None of the answers given is correct. 
A)  636 V/m 
B)  636 N/C 
C)  636 J/Cm 
D)  All of the answers given are correct. 
E)  None of the answers given is correct.

Exam 25: Electromagnetic Waves

The average electric energy density of an electromagnetic wave is 0.600 × 10-7 J/m3. What is the electric field component of this wave?

A 60.0-W light bulb radiates light uniformly in all different directions. What is the value of B at a distance of 0.700 m from the bulb?

Object A in the shape of a disk of radius r is placed a distance R away from an intense light source. Object B, made from the same material as object A, is in the shape of a disk of radius 2r and placed a distance 2R away from the same light source. We observe which of the following?

Which one of the following is the correct representation of the electromagnetic waves from longer wavelength to shorter wavelength?

A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest frequency associated with this portion of the spectrum?

Which one of the following is the correct representation of the relationship between the speed of a wave (v), frequency of the wave (f), and its wavelength (λ)?

In 1676 Romer announced what value for the speed of light?

A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the lowest frequency associated with this portion of the spectrum?

A vertically polarized beam of light of intensity 100 W/m2 passes through two polarizers. The first polarizer is making an angle of 20° with its transmission axis and the second one is making an angle of 40° with its transmission axis. What is the transmitted intensity of this beam of light?

The frequency of a microwave signal is 9.76 GHz. What is its wavelength in meters?

The rms value of the electric field component of an electromagnetic wave is 27.2 N/C. What is the maximum value of the electric field?

An electromagnetic wave is a result of electric and magnetic fields acting together.

The energy density of an electromagnetic wave is

The first scientific attempt to measure the speed of light was made by

The magnetic field component of the electromagnetic wave is 15.0 μT. What is the magnetic energy density of the wave?

Unpolarized light of intensity I passes through four Polaroid sheets whose polarizing angles are rotated 30° from each other so that the last sheet is aligned at 90° to the first. What is the intensity of the light emerging from the fourth sheet?

A radio station broadcasts at a frequency of 80 MHz. How far will this signal travel in 67 ms?

A Doppler weather radar operates at a frequency of 3.40 GHz. The wave from this radar system reflects from an approaching weather system moving with a speed of 39.0 m/s. What is the difference in frequency between the outgoing and returning waves?

The value of the magnetic field for a certain type of electromagnetic wave is 2.12 μT. What is the value of the electric field for that wave?

Introduction to Physics

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The average electric energy density of an electromagnetic wave is 0.600 × 10^-7 J/m³. What is the electric field component of this wave?

A vertically polarized beam of light of intensity 100 W/m² passes through two polarizers. The first polarizer is making an angle of 20° with its transmission axis and the second one is making an angle of 40° with its transmission axis. What is the transmitted intensity of this beam of light?