Question 1

The area of a rectangular loop of wire is 3.6 ×  10−310 ^ { - 3 }10−3   m2m ^ { 2 }m2  . The loop is placed in a uniform magnetic field that changes steadily from 0.20 T to 1.4 T in 1.6 s. The plane of the loop is perpendicular to the direction of the magnetic field. What is the magnitude of the induced emf in that loop?

Accepted Answer

A)  2.8 ×  10−310 ^ { - 3 }10−3  V
B)  2.7 ×  10−310 ^ { - 3 }10−3  V
C)  0 V
D)  1.8 ×  10−310 ^ { - 3 }10−3  V
E)  3.0 ×  10−310 ^ { - 3 }10−3  V

Question 2

Unpolarized light passes through a combination of two ideal polarizers. The transmission axes of the first polarizer and the second polarizer are at 30.0° to each other. What percentage of the original light gets through the combination?

Accepted Answer

A)  37.5%
B)  50%
C)  75%
D)  100%

Question 3

A long vertical wire carries a steady 70 A current. As shown in the figure, a pair of horizontal rails are 0.20 m apart. A 20-Ω resistor connects points a and b, at the end of the rails. A bar is in contact with the rails, and is moved by an external force with a constant horizontal velocity of 0.90 m/s to the right, as shown. The bar and the rails have negligible resistance. At the instant that the bar is 0.20 m from the wire, what are the induced current in the resistor and its direction through the resistor? (μ0 = 4π × 10-7 T ∙ m/A)  0 = 4π × 10-7 T ∙ m/A)    A) 0.63 μA, from a to b B) 0.63 μA, from b to a C) 0.32 μA, from a to b D) 0.32 μA, from b to a E) 1.9 μA, from b to a" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  0.63 μA, from a to b
B)  0.63 μA, from b to a
C)  0.32 μA, from a to b
D)  0.32 μA, from b to a
E)  1.9 μA, from b to a

Question 4

A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. How far away is the reflecting object? (c = 3.0 × 108 m/s)

Accepted Answer

A)  1.5 km
B)  3.0 km
C)  6.0 km
D)  9.0 km

Question 5

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?

Accepted Answer

A)  9.4%
B)  91%
C)  50%
D)  0%
E)  33%

Question 6

Which one of the following expressions is the correct representation for the speed of light in vacuum?

Accepted Answer

A)    ε0μ0\sqrt { \varepsilon _ { 0 } \mu _ { 0 } }ε0​μ0​c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​ 
B)    ε0/μ0\sqrt { \varepsilon _ { 0 } / \mu _ { 0 } }ε0​/μ0​c34,79.3,68.167,158.7,102.5,238c34.3,79.3,51.8,119.3,52.5,120c340,-704.7,510.7,-1060.3,512,-1067l0 -0c4.7,-7.3,11,-11,19,-11H40000v40H1012.3s-271.3,567,-271.3,567c-38.7,80.7,-84,175,-136,283c-52,108,-89.167,185.3,-111.5,232c-22.3,46.7,-33.8,70.3,-34.5,71c-4.7,4.7,-12.3,7,-23,7s-12,-1,-12,-1s-109,-253,-109,-253c-72.7,-168,-109.3,-252,-110,-252c-10.7,8,-22,16.7,-34,26c-22,17.3,-33.3,26,-34,26s-26,-26,-26,-26s76,-59,76,-59s76,-60,76,-60zM1001 80h400000v40h-400000z'/>​ 
C)    μ0/ε0\sqrt { \mu _ { 0 } / \varepsilon _ { 0 } }μ0​/ε0​c34,79.3,68.167,158.7,102.5,238c34.3,79.3,51.8,119.3,52.5,120c340,-704.7,510.7,-1060.3,512,-1067l0 -0c4.7,-7.3,11,-11,19,-11H40000v40H1012.3s-271.3,567,-271.3,567c-38.7,80.7,-84,175,-136,283c-52,108,-89.167,185.3,-111.5,232c-22.3,46.7,-33.8,70.3,-34.5,71c-4.7,4.7,-12.3,7,-23,7s-12,-1,-12,-1s-109,-253,-109,-253c-72.7,-168,-109.3,-252,-110,-252c-10.7,8,-22,16.7,-34,26c-22,17.3,-33.3,26,-34,26s-26,-26,-26,-26s76,-59,76,-59s76,-60,76,-60zM1001 80h400000v40h-400000z'/>​ 
D)  1 /  ε0μ0\sqrt { \varepsilon _ { 0 } \mu _ { 0 } }ε0​μ0​c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​ 
E)  1 / ?0?0

Question 7

As shown in the figure, two solenoids are in line. The switch S, initially closed, is suddenly opened. Just after opening S, what is the polarity of the induced emf in terminals X and Y?

Accepted Answer

A)  X and Y are at the same potential.
B)  X is positive and Y is negative.
C)  Y is positive and X is negative.

Question 8

As shown in the figure, a metal bar is in contact with a pair of parallel rails. A steady, uniform, magnetic field B is present directed to the right. The bar is moving upward with velocity of magnitude ν. What is the polarity of the induced emf in terminals X and Y?

Accepted Answer

A)  X and Y are at the same potential.
B)  X is positive and Y is negative.
C)  Y is positive and X is negative.

Question 9

The amplitude of the electric field for a certain type of electromagnetic wave is 570 N/C. What is the amplitude of the magnetic field for that wave? (c = 3.00 × 108 m/s)

Accepted Answer

A)  2.91 µT
B)  1.90 µT
C)  1.10 µT
D)  1.41 µT
E)  2.41 µT

Question 10

A giant star radiates energy at the rate of 3.0 × 1030 W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10-8 W/m2 ∙ K4)

Accepted Answer

A)  7.8 × 1010 m
B)  8.7 × 1010 m
C)  1.4 × 1010 m
D)  1.9 × 1011 m
E)  2.3 × 1011 m

Question 11

As shown in the figure, the orientation of the transmission axis for each of three ideal polarizing sheets is labeled relative to the vertical direction. A beam of light, polarized in the vertical direction, is incident on the first polarizer with an intensity of 1.00 kW/m2. What is the intensity of the beam after it has passed through the three polarizing sheets when θ1 = 30°, θ2 = 30°, and θ3= 60°? 2. What is the intensity of the beam after it has passed through the three polarizing sheets when θ1 = 30°, θ2 = 30°, and θ3= 60°?   A) 141 W/m2 B) 316 W/m2 C) 433 W/m2 D) 563 W/m2 E) 188 W/m2" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  141 W/m2
B)  316 W/m2
C)  433 W/m2
D)  563 W/m2
E)  188 W/m2

Question 12

As shown in the figure, a straight wire carries a steady current I. A metal bar is in contact with a pair of rails and is in upward motion with velocity of magnitude ν. The polarity of the induced emf in terminals X and Y is

Accepted Answer

A)  X and Y are at the same potential.
B)  X is positive and Y is negative.
C)  Y is positive and X is negative.

Question 13

Unpolarized light of intensity I0 passes through four ideal polarizing sheets. The polarizing angle of each sheet is rotated 30° from the one before it, so that the last sheet is aligned at 90° to the first sheet. What is the intensity of the light emerging from the fourth sheet in terms of I0?

Accepted Answer

Question 14

A circular wire ring is situated above a long straight wire, as shown in the figure. The straight wire has a current I flowing to the right, and this current is increasing at a constant rate. Which of the following statements is true?

Accepted Answer

A)  There is an induced current in the wire ring, directed in clockwise orientation.
B)  There is an induced current in the wire ring, directed in a counterclockwise orientation.
C)  There is no induced current in the wire ring.

Question 15

The rate of energy flow per unit area of an electromagnetic wave has an average value of 0.695 W/m2. The wave is incident at right angles upon a rectangular area measuring 1.5 m by 2.0 m. How much total energy falls upon this rectangle each minute? (ε0 = 8.85 × 10-12 C2/N ∙ m2, μ0 = 4π × 10-7 T ∙ m/A, c = 3.0 × 108 m/s)

Accepted Answer

A)  130 J
B)  160 J
C)  190 J
D)  220 J
E)  250 J

Question 16

How far does a beam of light travel in 2.0 ms? (c = 3.0 × 108 m/s)

Accepted Answer

A)  6.0 × 105 m
B)  0.66 × 105 m
C)  90 m
D)  70 m
E)  60 m

Question 17

Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength?

Accepted Answer

A)  radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
B)  radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
C)  radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
D)  radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
E)  radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays

Question 18

What is the photon energy of red light having a wavelength of 6.40 × 102 nm? (c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A)  1.13 × 10-19 J
B)  1.31 × 10-19 J
C)  3.11 × 10-19 J
D)  1.94 × 10-19 J

Question 19

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.

Accepted Answer

A)  0 T ∙ m2
B)  3.1 × 10-3 T ∙ m2
C)  5.5 × 10-3 T ∙ m2
D)  6.3 × 10-3 T ∙ m2

Question 20

A closed flat loop conductor with radius  2.0 m2.0 \mathrm {~m}2.0 m  is located in a changing uniform magnetic field. If the emf induced in the loop is  2.0 V2.0 \mathrm {~V}2.0 V  what is the rate at which the magnetic field strength is changing if the magnetic field is oriented perpendicular to the plane in which the loop lies?

Accepted Answer

A)  0.16 T/s
B)  1.0 T/s
C)  0.080 T/s
D)  2.0 T/s

Exam 25: Em Induction and Em Waves

As shown in the figure, a straight wire carries a steady current I. A metal bar is in contact with a pair of rails and is in upward motion with velocity of magnitude ν. The polarity of the induced emf in terminals X and Y is

Correct Answer
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As shown in the figure, a metal bar is in contact with a pair of parallel rails. A steady, uniform, magnetic field B is present directed to the right. The bar is moving upward with velocity of magnitude ν. What is the polarity of the induced emf in terminals X and Y?

Correct Answer
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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.

Correct Answer
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Which one of the following expressions is the correct representation for the speed of light in vacuum?

Correct Answer
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How far does a beam of light travel in 2.0 ms? (c = 3.0 × 10⁸ m/s)

Correct Answer
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A circular wire ring is situated above a long straight wire, as shown in the figure. The straight wire has a current I flowing to the right, and this current is increasing at a constant rate. Which of the following statements is true?

Correct Answer
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A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. How far away is the reflecting object? (c = 3.0 × 10⁸ m/s)

Correct Answer
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Correct Answer
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Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength?

Correct Answer
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A giant star radiates energy at the rate of 3.0 × 10³⁰ W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10^-8 W/m² ∙ K⁴)

Correct Answer
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Unpolarized light passes through a combination of two ideal polarizers. The transmission axes of the first polarizer and the second polarizer are at 30.0° to each other. What percentage of the original light gets through the combination?

Correct Answer
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The amplitude of the electric field for a certain type of electromagnetic wave is 570 N/C. What is the amplitude of the magnetic field for that wave? (c = 3.00 × 10⁸ m/s)

Correct Answer
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Correct Answer
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What is the photon energy of red light having a wavelength of 6.40 × 10² nm? (c = 3.00 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s)

Correct Answer
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As shown in the figure, two solenoids are in line. The switch S, initially closed, is suddenly opened. Just after opening S, what is the polarity of the induced emf in terminals X and Y?

Correct Answer
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Exam 25: Em Induction and Em Waves

As shown in the figure, a straight wire carries a steady current I. A metal bar is in contact with a pair of rails and is in upward motion with velocity of magnitude ν. The polarity of the induced emf in terminals X and Y is

Correct AnswerverifiedShow Answer

As shown in the figure, a metal bar is in contact with a pair of parallel rails. A steady, uniform, magnetic field B is present directed to the right. The bar is moving upward with velocity of magnitude ν. What is the polarity of the induced emf in terminals X and Y?

Correct AnswerverifiedShow Answer

Unpolarized light of intensity I0 passes through four ideal polarizing sheets. The polarizing angle of each sheet is rotated 30° from the one before it, so that the last sheet is aligned at 90° to the first sheet. What is the intensity of the light emerging from the fourth sheet in terms of I0?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which one of the following expressions is the correct representation for the speed of light in vacuum?

Correct AnswerverifiedShow Answer

How far does a beam of light travel in 2.0 ms? (c = 3.0 × 108 m/s)

Correct AnswerverifiedShow Answer

A circular wire ring is situated above a long straight wire, as shown in the figure. The straight wire has a current I flowing to the right, and this current is increasing at a constant rate. Which of the following statements is true?

Correct AnswerverifiedShow Answer

A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. How far away is the reflecting object? (c = 3.0 × 108 m/s)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which one of the following lists gives the correct order of the electromagnetic waves from longer wavelength to shorter wavelength?

Correct AnswerverifiedShow Answer

A giant star radiates energy at the rate of 3.0 × 1030 W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10-8 W/m2 ∙ K4)

Correct AnswerverifiedShow Answer

Unpolarized light passes through a combination of two ideal polarizers. The transmission axes of the first polarizer and the second polarizer are at 30.0° to each other. What percentage of the original light gets through the combination?

Correct AnswerverifiedShow Answer

The amplitude of the electric field for a certain type of electromagnetic wave is 570 N/C. What is the amplitude of the magnetic field for that wave? (c = 3.00 × 108 m/s)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is the photon energy of red light having a wavelength of 6.40 × 102 nm? (c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ∙ s)

Correct AnswerverifiedShow Answer

As shown in the figure, two solenoids are in line. The switch S, initially closed, is suddenly opened. Just after opening S, what is the polarity of the induced emf in terminals X and Y?

Correct AnswerverifiedShow Answer

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How far does a beam of light travel in 2.0 ms? (c = 3.0 × 10⁸ m/s)

Correct Answer
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Correct Answer
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A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. How far away is the reflecting object? (c = 3.0 × 10⁸ m/s)

Correct Answer
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Correct Answer
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Correct Answer
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A giant star radiates energy at the rate of 3.0 × 10³⁰ W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10^-8 W/m² ∙ K⁴)

Correct Answer
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Correct Answer
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The amplitude of the electric field for a certain type of electromagnetic wave is 570 N/C. What is the amplitude of the magnetic field for that wave? (c = 3.00 × 10⁸ m/s)

Correct Answer
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Correct Answer
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What is the photon energy of red light having a wavelength of 6.40 × 10² nm? (c = 3.00 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s)

Correct Answer
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Correct Answer
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