                        NCFE 2019 Part 2
Accessed 8 Sept 2019 at http://www.NCpublicschools.org

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21. What is the frequency of a light wave if its wavelength is 4.70 x 10-7 meters?
1. 6.38 x 1014 Hz
2. 6.32 x 107 Hz
3. 1.57 x 10-8 Hz
4. 1.57 x 10-15 Hz
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22. The diagram below shows a ray of light passing from air through a piece of glass and then back into air again. The ray of light has an angle of incidence of 60° to normal when it originally passes from air to the glass. Which angle is also equal to 60°?
1. W
2. X
3. Y
4. Z
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23. A blue light wave and a sound wave travel through air and then enter a glass block at an angle of incidence of 45°. Which statement best describes the motion of the waves as they travel through the glass block?
1. Each wave will move at the same speed that it had when it was traveling through air.
2. Each wave will have the same frequency that it had when it was traveling through air.
3. The blue light wave will decrease in speed, but the sound wave will increase in speed.
4. The blue light wave will increase in frequency, but the sound wave will decrease in frequency.
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24. The diagram below shows two 9.00-V batteries connected in series across a 6.00-Ω resistor. What is the current reading at the ammeter?
1. 0.667 A
2. 3.00 A
3. 54.0 A
4. 108 A
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25. An electrical appliance can work with a 12 V battery. It can also work by being plugged into a wall socket. What type of voltage conversion is needed between the wall socket and the appliance circuitry when the appliance is plugged into the wall socket?
1. 12 V AC is changing to 120 V DC.
2. 12 V DC is changing to 120 V AC.
3. 120 V AC is changing to 12 V DC.
4. 120 V DC is changing to 12 V AC.
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26. A 3-Î© resistor is connected to a 6-V source. What is the power rating of the circuit when the 6-V power source is changed to a 12-V source?
1. 2 W
2. 2 W
3. 36 W
4. 48 W
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27. The diagram below represents a DC circuit. The current flowing through the 8.0-Ω resistor is 1.0 A. What is the current flowing through the 6.0-Ω resistor?
1. 0.75 A
2. 1.0 A
3. 1.2 A
4. 1.3 A
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28. The circuits shown below are made using a battery, a lamp, and a rod. One circuit has a copper rod, and the other circuit has a rod made of glass. Which rod is better at making the lamp glow?
1. copper, because the electrons are tightly bound in copper
2. copper, because the electrons are free to move through copper
3. glass, because the electrons are free to move through glass
4. glass, because the electrons are tightly bound in glass
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29. A 60.0-W lightbulb in a 120-V lamp is left on for 3,600 seconds. What amount of energy does the lightbulb consume?
1. 2.16 x 105 J
2. 7.20 x 103 J
3. 6.00 x 101 J
4. 5.00 x 10-1 J
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30. Below are two diagrams of different circuits. How does the overall resistance in Circuit I compare to the overall resistance in Circuit II?
1. Circuit I has an overall resistance of 0.25 Ω, while Circuit II has an overall resistance of 18 Ω.
2. Circuit I has an overall resistance of 4.0 Ω, while Circuit II has a total resistance of 18 Ω.
3. Circuit I has an overall resistance of 18 Ω, while Circuit II has an overall resistance of 0.25 Ω.
4. Circuit I has an overall resistance of 18 Ω, while Circuit II has an overall resistance of 4.0 Ω.
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31. Two identical conducting spheres are brought near each other as seen in the figure below. Sphere I has a charge of +1 C, and Sphere II has a charge of +2 C. What is the direction of charge flow when they are touched together?
1. Protons will move from Sphere I to Sphere II.
2. Protons will move from Sphere II to Sphere I.
3. Electrons will move from Sphere I to Sphere II.
4. Electrons will move from Sphere II to Sphere I.
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32. The electric field strength between two parallel plates 42 cm apart is 840 V/m. What is the potential difference between them?
1. 110 V
2. 350 V
3. 2.0 Ã— 103 V
4. 3.5 Ã— 104 V
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33. Two point charges are located 2.1 m apart. One has a charge of 4.0 Ã— 10-6 C and the other has a charge of 6.0 Ã— 10-6 C. What is the electrostatic force between the charges?
1. 0.22 N
2. 0.10 N
3. 0.049 N
4. 0.032 N
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34. A negatively charged metal rod is brought into contact with a neutral metal sphere. Which is a description of the charge of each object after their contact?
1. The rod is positively charged and the sphere is negatively charged.
2. The rod is negatively charged and the sphere is positively charged.
3. The rod and the sphere are both positively charged.
4. The rod and the sphere are both negatively charged.
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35. An alpha particle is released above a positively charged plate as shown in the diagram below. The alpha particle is composed of two protons and two neutrons. How will the alpha particle react to the plate?
1. The particle has an overall neutral charge because the protons cancel the neutrons, so it will be attracted to the plate.
2. The particle has an overall neutral charge because the protons cancel the neutrons, so it will be repelled from the plate.
3. The particle has an overall positive charge because of the protons, so it will be repelled from the plate.
4. The particle has an overall negative charge because of the neutrons, so it will be attracted to the plate.
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36. A student touches a negatively charged rod to an uncharged electroscope. Which is the result?
1. A negative charge flows from the rod to the electroscope, and an equal positive charge flows from the electroscope to the rod.
2. A negative charge flows from the rod to the electroscope, and the leaves diverge.
3. A positive charge flows from the electroscope to the rod until the rod is neutral.
4. A positive charge is attracted to the head of the electroscope, but the leaves remain closed.
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37. Which diagram illustrates the magnetic domains of a permanent magnet? 1. Diagram A
2. Diagram B
3. Diagram C
4. Diagram D
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38. Which type of magnetic field is created by a straight, current-carrying wire?
1. a magnetic field of straight lines perpendicular to the wire
2. a magnetic field of straight lines parallel to the wire
3. a magnetic field that follows crossed lines originating from the wire
4. a magnetic field that follows a circular path around the wire
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39. What happens when an ideal step-up transformer increases the voltage of alternating current?
1. Alternating current can produce a large amount of energy; therefore, voltages increase, while current remains the same.
2. As the voltage is increased by the transformer, it decreases current proportionately to maintain the same power.
3. Alternating current induces voltage across the output wires of the transformer, thereby increasing electrical power.
4. The increased voltage in the output is a peak value, and over time the voltage drops to match the input value.
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40. An electromagnet is constructed by wrapping a current-carrying wire around an iron core. Which conditions will produce the strongest magnetic field?
1. 40 turns of a wire carrying 4 A current
2. 20 turns of a wire carrying 4 A current
3. 40 turns of a wire carrying 2 A current
4. 20 turns of a wire carrying 2 A current Additional North Carolina Exam Questions