What is the frequency of 20-mm microwaves? (c = 3.0 × 108 m/s)

A) 100 MHz B) 400 MHz C) 15 GHz D) 73 GHz A) 100 MHz B) 400 MHz C) 15 GHz D) 73 GHz

Polarized light of intensity S0 passes through an ideal polarizer. If the electric vector of the polarized light is horizontal what, in terms of the initial intensity S0, is the intensity of the light that passes through a polarizer if that polarizer is tilted 0.449 $\text{rad }$ from the horizontal?

A) 0.812 S0 B) 0.188 S0 C) 0.217 S0 D) 0.284 S0 A) 0.812 S0 B) 0.188 S0 C) 0.217 S0 D) 0.284 S0

Exam 25: EM Induction and Em Waves

At a certain instant in time, the electric field of an electromagnetic wave in free space points in the -z direction, and the magnetic field points in the +y direction. In what direction is this wave traveling?

(Multiple Choice)

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Question 141

A flat coil having 160 turns, each with an area of 0.20 m², is placed with the plane of its area perpendicular to a magnetic field of 0.40 T. The magnetic field changes uniformly from 0.40 T in the +x direction to 0.40 T in the -x direction in 2.0 s. If the resistance of the coil is 16 Ω, at what rate is power generated in the coil during this change?

(Multiple Choice)

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Question 142

For an electromagnetic wave in free space having an electric field of amplitude E and a magnetic field of amplitude B, the ratio of B/E is equal to

(Multiple Choice)

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Question 143

Unpolarized light passes through three ideal polarizing filters. The first filter is oriented with a horizontal transmission axis, the second one has its transmission axis at 30° from the horizontal, and the third filter has a vertical transmission axis. What percent of the light gets through this combination?

(Multiple Choice)

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Question 144

Unpolarized light is incident upon two ideal polarizing filters that do not have their transmission axes aligned. If $19 \%$ of the light passes through this combination, what is the angle between the transmission axes of the two filters?

(Multiple Choice)

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Question 145

According to Lenz's law, the induced current in a circuit always flows to oppose the external magnetic flux through the circuit.

(True/False)

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Question 146

A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are perpendicular.

(Multiple Choice)

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Question 147

What is the energy (in eV) of an optical photon of frequency $6.43 \times 10^{14} \mathrm {~Hz}$ (h = 6.626 × 10^-34 J ∙ s, 1 eV = 1.60 × 10^-19 J)

(Multiple Choice)

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Question 148

What is the frequency of 20-mm microwaves? (c = 3.0 × 10⁸ m/s)

(Multiple Choice)

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Question 149

Polarized light of intensity S₀ passes through an ideal polarizer. If the electric vector of the polarized light is horizontal what, in terms of the initial intensity S₀, is the intensity of the light that passes through a polarizer if that polarizer is tilted 0.449 $\text{rad }$ from the horizontal?

(Multiple Choice)

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Question 150

Which one of the following types of electromagnetic wave travels through space the fastest?

(Multiple Choice)

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Question 151

A flat rectangular coil with dimensions of 8.0 cm × 10 cm is dropped from a zero magnetic field position into a 1.4-T magnetic field in 0.10 s. The coil has 60 turns and is perpendicular to the magnetic field. What is the average induced emf in the coil as a result of this action?

(Multiple Choice)

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Question 152

Light of intensity S₀ that is polarized horizontally passes through three ideal polarizers. The first and third are horizontal, but the second one is oriented at 0.39270 $\text{rad}$ to the horizontal. In terms of S₀, the intensity of the light that passes through the set of polarizers is closest to which one of the following choices?

(Multiple Choice)

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Question 153

How much power does a sphere with a radius of 10 cm radiate into empty space if is has an emissivity of 1.0 and is kept at a temperature of 400 K? (σ = 5.67 × 10^-8 W/m² ∙ K⁴)

(Multiple Choice)

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Question 154

It is known that birds can detect the earth's magnetic field, but the mechanism of how they do this is not known. It has been suggested that perhaps they detect a motional emf as they fly north to south, but it turns out that the induced voltages are small compared to the voltages normally encountered in cells, so this is probably not the mechanism involved. To check this out, calculate the induced voltage across the wingtips of a wild goose with a wingspan of $1.2 \mathrm {~m}$ if it is flying directly south at $13 \mathrm {~m} / \mathrm { s }$ at a point where the earth's magnetic field is 5.0 ×10^-5 T directed downward from the horizontal by $40 ^ { \circ }$

(Multiple Choice)

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Question 155

In an electric furnace used for refining steel, the temperature is monitored by measuring the radiant power emitted through a small hole in the wall of the furnace, of area 0.5 cm². This hole acts like a perfect blackbody radiator having the same temperature as the interior of the furnace. If the temperature of the furnace (and therefore of the hole) is to be maintained at 1650°C, how much power will the hole radiate?

(Multiple Choice)

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Question 156

A laser beam takes 24 ms to travel from a rocket to the reflective surface of a planet and back to the rocket. How far is the rocket from this planet's surface? (c = 3.0 × 10⁸ m/s)

(Multiple Choice)

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Question 157

A 2.00-m long metal wire is formed into a square and placed in the horizontal xy-plane. A uniform magnetic field is oriented at 30° above the horizontal with a strength of 0.344 T. What is the magnetic flux through the square due to this field?

(Multiple Choice)

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Question 158

Which one of the following lists gives the correct order of the electromagnetic spectrum from low to high frequencies?

(Multiple Choice)

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Question 159

A round flat conducting loop is placed perpendicular to a uniform 0.50 T magnetic field. If the area of the loop increases at a rate of 3.0 × $10^{ - 3}$ $m ^ { 2 }$ /s, what is the induced emf in the loop?

(Multiple Choice)

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Question 160

Showing 141 - 160 of 185

Exam 25: EM Induction and Em Waves

At a certain instant in time, the electric field of an electromagnetic wave in free space points in the -z direction, and the magnetic field points in the +y direction. In what direction is this wave traveling?

For an electromagnetic wave in free space having an electric field of amplitude E and a magnetic field of amplitude B, the ratio of B/E is equal to

Unpolarized light is incident upon two ideal polarizing filters that do not have their transmission axes aligned. If 19%19 \%19% of the light passes through this combination, what is the angle between the transmission axes of the two filters?

According to Lenz's law, the induced current in a circuit always flows to oppose the external magnetic flux through the circuit.

A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are perpendicular.

What is the energy (in eV) of an optical photon of frequency 6.43×1014 Hz6.43 \times 10^{14} \mathrm {~Hz}6.43×1014 Hz (h = 6.626 × 10-34 J ∙ s, 1 eV = 1.60 × 10-19 J)

What is the frequency of 20-mm microwaves? (c = 3.0 × 108 m/s)

Which one of the following types of electromagnetic wave travels through space the fastest?

A flat rectangular coil with dimensions of 8.0 cm × 10 cm is dropped from a zero magnetic field position into a 1.4-T magnetic field in 0.10 s. The coil has 60 turns and is perpendicular to the magnetic field. What is the average induced emf in the coil as a result of this action?

How much power does a sphere with a radius of 10 cm radiate into empty space if is has an emissivity of 1.0 and is kept at a temperature of 400 K? (σ = 5.67 × 10-8 W/m2 ∙ K4)

A laser beam takes 24 ms to travel from a rocket to the reflective surface of a planet and back to the rocket. How far is the rocket from this planet's surface? (c = 3.0 × 108 m/s)

A 2.00-m long metal wire is formed into a square and placed in the horizontal xy-plane. A uniform magnetic field is oriented at 30° above the horizontal with a strength of 0.344 T. What is the magnetic flux through the square due to this field?

Which one of the following lists gives the correct order of the electromagnetic spectrum from low to high frequencies?

A round flat conducting loop is placed perpendicular to a uniform 0.50 T magnetic field. If the area of the loop increases at a rate of 3.0 × 10−310^{ - 3}10−3 m2m ^ { 2 }m2 /s, what is the induced emf in the loop?

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Filters

Unpolarized light is incident upon two ideal polarizing filters that do not have their transmission axes aligned. If $19 \%$ of the light passes through this combination, what is the angle between the transmission axes of the two filters?

What is the energy (in eV) of an optical photon of frequency $6.43 \times 10^{14} \mathrm {~Hz}$ (h = 6.626 × 10^-34 J ∙ s, 1 eV = 1.60 × 10^-19 J)

What is the frequency of 20-mm microwaves? (c = 3.0 × 10⁸ m/s)

How much power does a sphere with a radius of 10 cm radiate into empty space if is has an emissivity of 1.0 and is kept at a temperature of 400 K? (σ = 5.67 × 10^-8 W/m² ∙ K⁴)

A laser beam takes 24 ms to travel from a rocket to the reflective surface of a planet and back to the rocket. How far is the rocket from this planet's surface? (c = 3.0 × 10⁸ m/s)

A round flat conducting loop is placed perpendicular to a uniform 0.50 T magnetic field. If the area of the loop increases at a rate of 3.0 × $10^{ - 3}$ $m ^ { 2 }$ /s, what is the induced emf in the loop?