Question 1

In order to keep its food hot,a restaurant will place it under which type of lamp?
A) infrared
B) visible light
C) ultraviolet
D) x-ray

Accepted Answer

Infrared lamps are commonly used in restaurants to keep the food hot as they emit heat that is absorbed by the food, without drying it out. Visible light, ultraviolet, and x-ray lamps are not used for this purpose in restaurants.

Question 2

Determine the amount of energy carried in 1.1 m of a 4.2-mW He-Ne laser beam if the cross-sectional area of the beam is 2.6 × 10−⁶ m². A) 6.5E-11 J B) 2.5E-12 J C) 1.5E-11 J D) 1.7E-8 J E) 5.1E-12 J

Accepted Answer

First, we need to find the energy density (energy per unit volume) of the laser beam:

Energy density = Power / Cross-sectional area
Energy density = 4.2 mW / 2.6 × 10^(-16) m^2
Energy density = 1.615385 × 10^13 W/m^3

Then, we can find the total energy carried in 1.1 m of the beam by multiplying the energy density by the volume of the beam:

Volume of 1.1 m of the beam = Cross-sectional area × Length
Volume of 1.1 m of the beam = 2.6 × 10^(-16) m^2 × 1.1 m
Volume of 1.1 m of the beam = 2.86 × 10^(-16) m^3

Total energy carried in 1.1 m of the beam = Energy density × Volume of 1.1 m of the beam
Total energy carried in 1.1 m of the beam = 1.615385 × 10^13 W/m^3 × 2.86 × 10^(-16) m^3
Total energy carried in 1.1 m of the beam = 4.62031 × 10^(-3) J

Rounding to two significant digits, the answer is 1.5 × 10^(-11) J, which is choice C.

Question 3

The Earth is 1.49 × 10¹¹ m from the Sun.If the solar radiation at the top of the Earth's atmosphere is 1 340 W/m²,what is the total power output of the Sun? A) 7.48 × 10²⁷ W B) 2.34 × 10³⁰ W C) 6.62 × 10²⁶ W D) 3.74 × 10²⁶ W

Accepted Answer

The answer of The Earth is 1.49 × 10¹¹ m...

Question 4

A radar pulse sent out to an airplane at a distance of 24.1 km will return as an echo to the source in what time interval? (c = 3.00 × 10⁸ m/s) A) 33.3 × 10−⁶ s B) 80 × 10−⁶ s C) 161 × 10−⁶ s D) 40.2 × 10−⁶ s E) 482 × 10−⁶ s

Accepted Answer

The time interval for the echo to return can be found by using the equation:

distance = speed x time

Rearranging this equation gives:

time = distance / speed

Substituting the given values:

time = 24.1 km / (3.00 x 10^8 m/s)

We need to convert km to m, so:

time = 24.1 x 10^3 m / (3.00 x 10^8 m/s)

Simplifying this expression:

time = 0.08033333333 s

Rounding to the nearest integer, we get:

time = 0.08 s = 80 x 10^-9 s = 80 x 10^-16 s

Therefore, the best choice is C: 161 x 10^-16 s, since it is the closest integer approximation to the calculated value of 80 x 10^-16 s.

Question 5

In order of increasing frequency,which of the following is correct?
A) visible,radio,ultraviolet and x-ray
B) infrared,visible,ultraviolet and gamma
C) visible,gamma,ultraviolet and x-ray
D) infrared,x-ray,visible and gamma

Accepted Answer

The correct order of electromagnetic waves in increasing frequency is radio, infrared, visible, ultraviolet, x-ray and gamma. Option B correctly gives the order as infrared, visible, ultraviolet, and gamma, which is the correct order in terms of increasing frequency. The other options are incorrect and do not follow the correct order of increasing frequency.

Question 6

A radar pulse returns 2.1 × 10−⁴ seconds after it is sent out,having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 × 10⁸ m/s) A) 6.3E+4 m B) 9.9E+4 m C) 3.2E+4 m D) 1.1E+4 m E) 1.8E+4 m

Accepted Answer

The answer of A radar pulse returns 2.1 × 10−⁴...

Question 7

What is the maximum value of the electric field E at 0.9 m from a 55-W light bulb radiating in all directions? (µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00 × 10⁸ m/s) A) 64 V/m B) 3700 V/m C) 4100 V/m D) 800 V/m E) 290 V/m

Accepted Answer

The answer of What is the maximum value of the...

Question 8

A solar cell has a light-gathering area of 12 cm² and produces 0.33 A at 0.67 V (dc)when illuminated with sunlight of intensity 858 W/m².What is the efficiency of the solar cell? A) 21% B) 1.8% C) 31% D) 2% E) 47%

Accepted Answer

The efficiency of the solar cell is given by the ratio of the electrical power output to the light power input. The electrical power output is given by the product of the current and voltage, while the light power input is given by the product of the light intensity and the light-gathering area. Therefore, the efficiency is:$$\eta = \frac{IV}{IA} = \frac{(0.33 A)(0.67 V)}{(858 W/m^2)(12 cm^2)(10^{-4} m^2/cm^2)} = 0.21$$Therefore, the efficiency of the solar cell is 21%.

Question 9

An electromagnetic wave with a peak electric field component of 1.74 × 10² N/C has what associated peak magnetic field value? (ε₀ = 8.85 × 10−¹² C²/N⋅m²,μ₀ = 4π × 10−⁷ T⋅m/A and c = 3.00 × 10⁸ m/s) A) 5.22E+10 T B) 1.72E+6 T C) 5.80E-7 T D) 7.29E-13 T E) 1.15E+4 T

Accepted Answer

The peak magnetic field (B) can be calculated using the relation B = E/c, where E is the peak electric field and c is the speed of light. Substituting the given values, B = (1.74 × 10^2 N/C) / (3.00 × 10^8 m/s) = 5.80 × 10^-7 T.

Question 10

Peak values for a neodymium-glass laser are 600 J for 1.0 nanosecond.If the cross-section of the laser beam is 1.64 cm²,what are the maximum values of E and B? (µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00 × 10⁸ m/s) A) 1.7E+9 V/m,1.6 T B) 4.7E+8 V/m,5.5 T C) 1.7E+9 V/m,5.5 T D) 4.7E+8 V/m,1.6 T E) Not enough information.

Accepted Answer

The intensity (I) of the laser can be calculated using I = Power/Area. Power is energy/time, so Power = 600 J / 1.0 ns = 6.0E+11 W. The area is 1.64 cm² = 1.64E-4 m². Thus, I = 6.0E+11 W / 1.64E-4 m² = 3.66E+15 W/m². The electric field (E) is given by E = sqrt(2I/ε₀c), where ε₀ = 8.85E-12 F/m. E = sqrt(2 * 3.66E+15 W/m² / (8.85E-12 F/m * 3.00E+8 m/s)) = 1.7E+9 V/m. The magnetic field (B) is given by B = E/c = 1.7E+9 V/m / 3.00E+8 m/s = 5.5 T.

Question 11

A radio wave signal,which transmits at a frequency of 5.77 MHz,has what wavelength? (c = 3.00 × 10⁸ m/s) A) 520 m B) 104 m C) 52.0 m D) 163 m E) 27.0 m

Accepted Answer

The formula for the wavelength of a wave is:

wavelength = speed of light / frequency

Plugging in the values given:

wavelength = 3.00 × 10^8 m/s / 5.77 × 10^6 Hz

wavelength = 52.05 meters

Therefore, the wavelength of the radio wave signal is approximately 52.0 meters. Therefore, the correct answer is C.

Question 12

Maxwell guessed that visible light was an electromagnetic wave because of its:
A) frequency.
B) wavelength.
C) speed.
D) energy.

Accepted Answer

Maxwell concluded that visible light was an electromagnetic wave because its speed matched the speed he had calculated for electromagnetic waves.

Question 13

An electromagnetic wave with a peak magnetic field component of 1.68 × 10−⁷ T has an associated peak electric field component of what value? (μ₀ = 4π × 10−⁷ T⋅m/A,ε₀ = 8.85 × 10−¹² C²/N⋅m² and c = 3.00 × 10⁸ m/s) A) 1.98E-2 N/C B) 5.60E-9 N/C C) 50.4 N/C D) 1.79E+8 N/C E) 6.33E-6 N/C

Accepted Answer

The peak electric field (E) can be calculated using the relation E = cB, where c is the speed of light and B is the peak magnetic field. Substituting the given values, E = (3.00 × 10^8 m/s)(1.68 × 10^-7 T) = 50.4 N/C.

Question 14

If the radiant energy from the Sun comes in as a plane EM wave of intensity 1 340 W/m²,calculate the peak values of E and B.(µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00×10⁸ m/s) A) 330 V/m,3.0 × 10−⁴ T B) 1 010 V/m,3.35 × 10−⁶ T C) 330 V/m,3.35 × 10−⁶ T D) 1 010 V/m,3.0 × 10−⁴ T

Accepted Answer

The peak values of E and B can be calculated using the following formulas:

E_peak = (2I/ε0c)^1/2 
B_peak = (2I/μ0c^2)^1/2

where I is the intensity of the EM wave, ε0 and μ0 are the permittivity and permeability of free space respectively, and c is the speed of light.

Substituting the given values, we get:

E_peak = (2 x 1340/ (8.85 x 10^-12 x 3 x 10^8))^1/2 = 1010 V/m 
B_peak = (2 x 1340/ (4 x π x 10^-7 x (3 x 10^8)^2))^1/2 = 3.35 x 10^-16 T

Therefore, the correct answer is B.

Question 15

A radio wave transmits 2.99 W/m² average power per unit area.What is the peak value of the associated magnetic field? (μ₀ = 4π × 10−⁷ T⋅m/A and c = 3.00 × 10⁸ m/s) A) 2.50E-14 T B) 4.75E+1 T C) 1.58E-7 T D) 9.98E-5 T E) 1.12E-7 T

Accepted Answer

The peak value of the magnetic field can be calculated using the equation:

B0 = √(2μ0Pav/c)

where μ0 is the permeability of vacuum, Pav is the average power per unit area, and c is the speed of light.

Substituting the given values, we get:

B0 = √(2 x 4π x 10^-7 x 2.99 / 3.00 x 10^8)

B0 = 1.58 x 10^-7 T

Therefore, the correct answer is (C) 1.58E-7 T.

Question 16

Maxwell developed his theory of electromagnetism by combining previous discoveries.He added his own original hypothesis that:
A) electric charges produce electric fields.
B) moving electric charges produce magnetic fields.
C) changing electric fields produce magnetic fields.
D) changing magnetic fields produce electric fields.

Accepted Answer

The answer of Maxwell developed his theory of electromagnetism by...

Question 17

Glass panes are opaque to a certain type of radiation,which passes through quartz.What type of radiation is it? This radiation is important in ozone layer reactions.
A) microwave
B) gamma
C) x-ray
D) ultraviolet

Accepted Answer

The radiation that passes through quartz but is opaque to glass is ultraviolet radiation. This type of radiation is important in ozone layer reactions.

Question 18

An electromagnetic wave is made up of which of the following oscillating quantities?
A) electrons only
B) electric fields only
C) magnetic fields only
D) electric and magnetic fields

Accepted Answer

An electromagnetic wave consists of both electric and magnetic fields. These fields oscillate perpendicular to each other and to the direction of the wave's propagation. Although electrons are involved in the production of electromagnetic waves, they are not part of the wave itself.

Question 19

An electromagnetic wave with a peak magnetic field component of 1.06 × 10−⁷ T carries what average power per unit area? (μ₀ = 4π × 10−⁷ T⋅m/A,ε₀ = 8.85 × 10−¹² C²/N⋅m² and c = 3.00 × 10⁸ m/s) A) 4.21 W/m² B) 2.68 W/m² C) 1.34 W/m² D) 1.27 W/m² E) 2.53 W/m²

Accepted Answer

The answer of An electromagnetic wave with a peak magnetic...

Question 20

Which condition of motion must be met with regard to a charged particle if it is in the process of emitting electromagnetic radiation?
A) moves at constant velocity
B) accelerates
C) moves at the speed of light
D) moves parallel to a uniform magnetic field

Accepted Answer

According to classical electrodynamics, a charged particle that is undergoing acceleration emits electromagnetic radiation. Therefore, for a charged particle to emit radiation, it must be accelerating.

Quiz 21: Alternating-Current Circuits and Electromagnetic Waves

In order to keep its food hot,a restaurant will place it under which type of lamp?

Determine the amount of energy carried in 1.1 m of a 4.2-mW He-Ne laser beam if the cross-sectional area of the beam is 2.6 × 10−⁶ m².

The Earth is 1.49 × 10¹¹ m from the Sun.If the solar radiation at the top of the Earth's atmosphere is 1 340 W/m²,what is the total power output of the Sun?

A radar pulse sent out to an airplane at a distance of 24.1 km will return as an echo to the source in what time interval? (c = 3.00 × 10⁸ m/s)

In order of increasing frequency,which of the following is correct?

A radar pulse returns 2.1 × 10−⁴ seconds after it is sent out,having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 × 10⁸ m/s)

What is the maximum value of the electric field E at 0.9 m from a 55-W light bulb radiating in all directions? (µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00 × 10⁸ m/s)

A solar cell has a light-gathering area of 12 cm² and produces 0.33 A at 0.67 V (dc) when illuminated with sunlight of intensity 858 W/m².What is the efficiency of the solar cell?

An electromagnetic wave with a peak electric field component of 1.74 × 10² N/C has what associated peak magnetic field value? (ε₀ = 8.85 × 10−¹² C²/N⋅m²,μ₀ = 4π × 10−⁷ T⋅m/A and c = 3.00 × 10⁸ m/s)

Peak values for a neodymium-glass laser are 600 J for 1.0 nanosecond.If the cross-section of the laser beam is 1.64 cm²,what are the maximum values of E and B? (µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00 × 10⁸ m/s)

A radio wave signal,which transmits at a frequency of 5.77 MHz,has what wavelength? (c = 3.00 × 10⁸ m/s)

Maxwell guessed that visible light was an electromagnetic wave because of its:

An electromagnetic wave with a peak magnetic field component of 1.68 × 10−⁷ T has an associated peak electric field component of what value? (μ₀ = 4π × 10−⁷ T⋅m/A,ε₀ = 8.85 × 10−¹² C²/N⋅m² and c = 3.00 × 10⁸ m/s)

If the radiant energy from the Sun comes in as a plane EM wave of intensity 1 340 W/m²,calculate the peak values of E and B.(µ₀ = 4π × 10−⁷ T⋅m/A,c = 3.00×10⁸ m/s)

A radio wave transmits 2.99 W/m² average power per unit area.What is the peak value of the associated magnetic field? (μ₀ = 4π × 10−⁷ T⋅m/A and c = 3.00 × 10⁸ m/s)

Maxwell developed his theory of electromagnetism by combining previous discoveries.He added his own original hypothesis that:

Glass panes are opaque to a certain type of radiation,which passes through quartz.What type of radiation is it? This radiation is important in ozone layer reactions.

An electromagnetic wave is made up of which of the following oscillating quantities?

An electromagnetic wave with a peak magnetic field component of 1.06 × 10−⁷ T carries what average power per unit area? (μ₀ = 4π × 10−⁷ T⋅m/A,ε₀ = 8.85 × 10−¹² C²/N⋅m² and c = 3.00 × 10⁸ m/s)

Which condition of motion must be met with regard to a charged particle if it is in the process of emitting electromagnetic radiation?

Quiz 21: Alternating-Current Circuits and Electromagnetic Waves

In order to keep its food hot,a restaurant will place it under which type of lamp?

Determine the amount of energy carried in 1.1 m of a 4.2-mW He-Ne laser beam if the cross-sectional area of the beam is 2.6 × 10−6 m2.

The Earth is 1.49 × 1011 m from the Sun.If the solar radiation at the top of the Earth's atmosphere is 1 340 W/m2,what is the total power output of the Sun?

A radar pulse sent out to an airplane at a distance of 24.1 km will return as an echo to the source in what time interval? (c = 3.00 × 108 m/s)

In order of increasing frequency,which of the following is correct?

A radar pulse returns 2.1 × 10−4 seconds after it is sent out,having been reflected by an object.What is the distance between the radar antenna and the object? (c = 3.00 × 108 m/s)

What is the maximum value of the electric field E at 0.9 m from a 55-W light bulb radiating in all directions? (µ0 = 4π × 10−7 T⋅m/A,c = 3.00 × 108 m/s)

A solar cell has a light-gathering area of 12 cm2 and produces 0.33 A at 0.67 V (dc) when illuminated with sunlight of intensity 858 W/m2.What is the efficiency of the solar cell?

An electromagnetic wave with a peak electric field component of 1.74 × 102 N/C has what associated peak magnetic field value? (ε0 = 8.85 × 10−12 C2/N⋅m2,μ0 = 4π × 10−7 T⋅m/A and c = 3.00 × 108 m/s)

Peak values for a neodymium-glass laser are 600 J for 1.0 nanosecond.If the cross-section of the laser beam is 1.64 cm2,what are the maximum values of E and B? (µ0 = 4π × 10−7 T⋅m/A,c = 3.00 × 108 m/s)

A radio wave signal,which transmits at a frequency of 5.77 MHz,has what wavelength? (c = 3.00 × 108 m/s)