Question Bank: Electric and Magnetic Fields in Vacuum |
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\[1\star\]
What results from the acceleration of electric charges?
Electric field only-C
Electromagnetic waves-A
Direct current-D
Magnetic field only-B
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Choose the correct answer
\[2\star\]
Radio waves, microwaves, and X-rays - which of the following correctly describes them?
Radio waves have same frequency - C
and wavelength and speed as other waves in vacuum
Radio waves have highest frequency, speed -A
shortest wavelength and highest
X-rays have highest frequency and shortest -D
wavelength and same speed as other waves in vacuum
Microwaves have highest frequency, shortestspeed
-B
wavelength and lowest
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\[3\star\]
What is the function of the oscillator in a radio circuit?
Amplify sound only-C
Store energy-A
Convert AC to DC-D
Generate fixed frequency-B
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\[4\star\]
What is the effect of increasing frequency on the wavelength of an electromagnetic wave?
No effect on wavelength -C
Makes it irregular -A
Wavelength decreases-D
Wavelength increases -B
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\[5\star\]
If the dielectric constant of glass equals \[ K=2.28 \], then the speed of light in glass equals
\[v= 1.5×10^{8} \;\;m/S\;\;\;\;\;\;-C\]
\[v= 1.3×10^{8} \;\;m/S\;\;\;\;\;\;-A\]
\[v= 2×10^{8} \;\;m/S\;\;\;\;\;\;-D\]
\[v= 2.5×10^{8} \;\;m/S\;\;\;\;\;\;-B\]
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\[6\star\]
One of the following answers is not a characteristic of electromagnetic waves
All electromagnetic waves are visible -C
All electromagnetic waves travel at -A
the same speed in vacuum
As frequency increases, energy increases -D
Electromagnetic waves do not need
-B
a medium to propagate
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\[7\star\]
The wavelength of blue light is \[λ=5×10^{-7} m\]
Then the frequency of the light equals
given that the speed of light is \[C=3 ×10^8 m\S\]
\[f=2.5×10^{14} \;\;Hz\;\;\;\;\;\;-C\]
\[f=6×10^{14} \;\;Hz\;\;\;\;\;\;-A\]
\[f=5×10^{14} \;\;Hz\;\;\;\;\;\;-D\]
\[f=4×10^{14} \;\;Hz\;\;\;\;\;\;-B\]
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\[8\star\]
Which of the following devices depends on electromagnetic waves?
Radio - C
Microwave - A
All of the above - D
Mobile phone - B
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\[9\star\]
One of the electromagnetic waves has the longest wavelength and lowest frequency
Visible light waves - C
Gamma rays - A
Ultraviolet rays - D
Ultraviolet rays - B
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\[10\star\]
If an electromagnetic wave propagates to the right
and the electric field points inward and outward
then the magnetic field points toward
East and West - C
North and South - A
East and West - D
North and East - B
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Choose the correct answer
\[11\star\]
One of the following statements does not represent properties of electromagnetic waves
Produced by oscillating charges - C
Propagate in all media at the same speed - A
Their energy increases with frequency - D
Electromagnetic waves are transverse - B
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\[12\star\]
A certain electromagnetic wave has a frequency higher than visible light. The wavelength of this wave is longer than the wavelength of X-rays.
Gamma Wave -C
Microwave -A
Infrared Wave -D
Ultraviolet Wave -B
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Physics Problems - Electromagnetic Waves
Physics Problems - Electromagnetic Waves
Problem 1: Classifying Waves by Frequency
Arrange the following types of electromagnetic waves from lowest to highest frequency: X-rays, radio waves, visible light, infrared, ultraviolet.
Solution:
The correct order from lowest to highest frequency is:
- Radio waves
- Infrared
- Visible light
- Ultraviolet
- X-rays
This order corresponds to the known electromagnetic spectrum.
Problem 2: Properties of Electromagnetic Waves
Complete the following table showing properties of some types of electromagnetic waves:
Wave Type
Wavelength (m)
Frequency (Hz)
Applications
Dielectric Constant (K)
Wave Speed (m/s)
Radio waves
1 → 104
?
?
1 (Air)
3×108
Infrared
?
1012 → 4.3×1014
?
2.3 (Polyethylene)
?
Visible light
400 → 700 nm
?
?
? (Glass)
2.45×108
Solution:
Wave Type
Wavelength (m)
Frequency (Hz)
Applications
Dielectric Constant (εr)
Wave Speed (m/s)
Radio waves
1 - 104
3×104 → 3×108
Radio broadcasting, wireless communications
1 (Air)
3×108
Infrared
7×10-7 → 3×10-4
1012 → 4.3×1014
Thermal imaging, remote controls
2.3 (Polyethylene)
1.98×108
Visible light
400 → 700 nm
4.3×1014 → 7.5×1014
Vision, optical communications
1.5 (Glass)
2.45×108
Note: Frequencies were calculated using the relation f = c/λ where c = 3×108 m/s
Note: Wave speeds in different media were calculated using v = c/√K
Problem 3: Properties of Electromagnetic Waves
List four fundamental properties of electromagnetic waves.
Solution:
- They travel through vacuum and don't need a medium.
- They travel at the speed of light (3 × 108 m/s in vacuum).
- They are transverse waves with electric and magnetic field oscillations perpendicular to the direction of propagation.
- They exhibit diffraction, interference, reflection and refraction like other waves.
- They vary by frequency and wavelength, forming the electromagnetic spectrum.
Problem 4: Calculating Wavelength in a Medium
An electromagnetic wave with frequency 600 Hz travels in a material with refractive index 2.0. Calculate the wavelength of this wave in this material.
To calculate the wavelength in the material:
1. Calculate the wavelength in vacuum:
λ₀ = c / f
Where:
- c = 3 × 108 m/s
- f = 600 THz = 600 × 1012 Hz
λ₀ = (3 × 108) / (600 × 1012) = 5 × 10-7 m = 500 nm
2. Calculate the wavelength in the material:
λ = λ₀ / n
Where n = 2.0
λ = 500 nm / 2.0 = 250 nm
Therefore, the wavelength in the material is 250 nanometers.
What results from the acceleration of electric charges?
Electric field only-C |
Electromagnetic waves-A |
Direct current-D |
Magnetic field only-B |
Click here to show solution
Choose the correct answer
Radio waves, microwaves, and X-rays - which of the following correctly describes them?
Radio waves have same frequency - C |
Radio waves have highest frequency, speed -A
|
X-rays have highest frequency and shortest -D |
Microwaves have highest frequency, shortestspeed
-B
|
Click here to show solution
Choose the correct answer
What is the function of the oscillator in a radio circuit?
Amplify sound only-C |
Store energy-A |
Convert AC to DC-D |
Generate fixed frequency-B |
Click here to show solution
Choose the correct answer
What is the effect of increasing frequency on the wavelength of an electromagnetic wave?
No effect on wavelength -C |
Makes it irregular -A |
Wavelength decreases-D |
Wavelength increases -B |
Click here to show solution
Choose the correct answer
If the dielectric constant of glass equals \[ K=2.28 \], then the speed of light in glass equals
\[v= 1.5×10^{8} \;\;m/S\;\;\;\;\;\;-C\] |
\[v= 1.3×10^{8} \;\;m/S\;\;\;\;\;\;-A\] |
\[v= 2×10^{8} \;\;m/S\;\;\;\;\;\;-D\] |
\[v= 2.5×10^{8} \;\;m/S\;\;\;\;\;\;-B\] |
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Choose the correct answer
One of the following answers is not a characteristic of electromagnetic waves
All electromagnetic waves are visible -C |
All electromagnetic waves travel at -A
|
As frequency increases, energy increases -D |
Electromagnetic waves do not need
-B
|
Click here to show solution
Choose the correct answer
The wavelength of blue light is \[λ=5×10^{-7} m\]
Then the frequency of the light equals
given that the speed of light is \[C=3 ×10^8 m\S\]
\[f=2.5×10^{14} \;\;Hz\;\;\;\;\;\;-C\] |
\[f=6×10^{14} \;\;Hz\;\;\;\;\;\;-A\] |
\[f=5×10^{14} \;\;Hz\;\;\;\;\;\;-D\] |
\[f=4×10^{14} \;\;Hz\;\;\;\;\;\;-B\] |
Click here to show solution
Choose the correct answer
Which of the following devices depends on electromagnetic waves?
Radio - C |
Microwave - A |
All of the above - D |
Mobile phone - B |
Click here to show solution
Choose the correct answer
One of the electromagnetic waves has the longest wavelength and lowest frequency
Visible light waves - C |
Gamma rays - A |
Ultraviolet rays - D |
Ultraviolet rays - B |
Click here to show solution
Choose the correct answer
If an electromagnetic wave propagates to the right
and the electric field points inward and outward
then the magnetic field points toward
East and West - C |
North and South - A |
East and West - D |
North and East - B |
Click here to show solution
Choose the correct answer
One of the following statements does not represent properties of electromagnetic waves
Produced by oscillating charges - C |
Propagate in all media at the same speed - A |
Their energy increases with frequency - D |
Electromagnetic waves are transverse - B |
Click here to show solution
Choose the correct answer
A certain electromagnetic wave has a frequency higher than visible light. The wavelength of this wave is longer than the wavelength of X-rays.
Gamma Wave -C |
Microwave -A |
Infrared Wave -D |
Ultraviolet Wave -B |
Click here to show solution method
Choose the correct answer
Physics Problems - Electromagnetic Waves
Problem 1: Classifying Waves by Frequency
Arrange the following types of electromagnetic waves from lowest to highest frequency: X-rays, radio waves, visible light, infrared, ultraviolet.
Solution:
The correct order from lowest to highest frequency is:
- Radio waves
- Infrared
- Visible light
- Ultraviolet
- X-rays
This order corresponds to the known electromagnetic spectrum.
Problem 2: Properties of Electromagnetic Waves
Complete the following table showing properties of some types of electromagnetic waves:
| Wave Type | Wavelength (m) | Frequency (Hz) | Applications | Dielectric Constant (K) | Wave Speed (m/s) |
|---|---|---|---|---|---|
| Radio waves | 1 → 104 | ? | ? | 1 (Air) | 3×108 |
| Infrared | ? | 1012 → 4.3×1014 | ? | 2.3 (Polyethylene) | ? |
| Visible light | 400 → 700 nm | ? | ? | ? (Glass) | 2.45×108 |
Solution:
| Wave Type | Wavelength (m) | Frequency (Hz) | Applications | Dielectric Constant (εr) | Wave Speed (m/s) |
|---|---|---|---|---|---|
| Radio waves | 1 - 104 | 3×104 → 3×108 | Radio broadcasting, wireless communications | 1 (Air) | 3×108 |
| Infrared | 7×10-7 → 3×10-4 | 1012 → 4.3×1014 | Thermal imaging, remote controls | 2.3 (Polyethylene) | 1.98×108 |
| Visible light | 400 → 700 nm | 4.3×1014 → 7.5×1014 | Vision, optical communications | 1.5 (Glass) | 2.45×108 |
Note: Frequencies were calculated using the relation f = c/λ where c = 3×108 m/s
Note: Wave speeds in different media were calculated using v = c/√K
Problem 3: Properties of Electromagnetic Waves
List four fundamental properties of electromagnetic waves.
Solution:
- They travel through vacuum and don't need a medium.
- They travel at the speed of light (3 × 108 m/s in vacuum).
- They are transverse waves with electric and magnetic field oscillations perpendicular to the direction of propagation.
- They exhibit diffraction, interference, reflection and refraction like other waves.
- They vary by frequency and wavelength, forming the electromagnetic spectrum.
Problem 4: Calculating Wavelength in a Medium
An electromagnetic wave with frequency 600 Hz travels in a material with refractive index 2.0. Calculate the wavelength of this wave in this material.
To calculate the wavelength in the material:
1. Calculate the wavelength in vacuum:
Where:
- c = 3 × 108 m/s
- f = 600 THz = 600 × 1012 Hz
λ₀ = (3 × 108) / (600 × 1012) = 5 × 10-7 m = 500 nm
2. Calculate the wavelength in the material:
Where n = 2.0
λ = 500 nm / 2.0 = 250 nm
Therefore, the wavelength in the material is 250 nanometers.
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