Physics 2 concept questions leftwich, exam 2
If three uncharged styrofoam balls are placed together and agitated so that one gains +3 C of charge and another gains +4 C of charge, how much charge must there be on the third one?
-7C If there was no charge to begin with, whatever positive charge the two balls gained must have left an equal amount of negative charge behind on the third because the total charge in any closed system must be conserved.
A positive charge is moved from point A to point B along an equipotential surface. How much work is performed or required in moving the charge? A> Work is both performed and required in moving the charge from point A to point B. B> Work is required in moving the positive charge from point A to point B. C> Work is performed in moving the positive charge from point A to point B. D> No work is performed or required in moving the positive charge from point A to point B.
D> No work is performed or required in moving the positive charge from point A to point B.
You are holding a positive charge and there are positive charges of equal magnitude 1 m to your north and 1 m to your east. What is the direction of the force on the charge you are holding?
to the southwest The total force is determined by the vector addition of the force from the north charge and the force from the east charge. However, because both charges are the same magnitude and the same distance away from you, the forces are also the same magnitude. Therefore, the net force is the vector sum of the two and the direction of the force on the charge you are holding should be to the southwest (equally to the west and the south).
A 1.97-pF capacitor with a plate area of 5.86 cm2 and separation between the plates of 2.63 mm is connected to a 9.0-V battery and fully charged. Then the separation between the plates is adjusted so that the energy stored in the capacitor is increased by a factor of 3.5. What is the new plate separation distance? 2.63 mm 0.752 mm 13.3 mm 75.2 mm
0.752mm The energy stored in a capacitor is U=12C(ΔV)2. If the stored energy increases by a factor of 3.5, so must the capacitance because the voltage across the capacitor remains constant at ΔV=ΔVbat=9.0 V. Recall that the capacitance for a parallel-plate capacitor is C=ϵ0Ad, where A is the area of one of the plates, d is the plate separation distance, and ϵ0 is the permittivity of free space. So, the new plate separation distance is d=ϵ0AC=(8.85×10−12 C2/N⋅m2)5.86×10−4 m23.5(1.97×10−12 F)=0.752 mm.
A parallel-plate capacitor has a capacitance of 1.97 pF and a plate area of 5.86 cm2. What is the separation distance between the plates? 2.63 mm 2.63 × 10-11 m 1.54 µm 0.263 m 15.4 mm
2.63 mm For a parallel-plate capacitor, the capacitance is C=ϵ0Ad, where A is the area of one of the plates, d is the plate separation distance, and ϵ0 is the permittivity of free space. The spacing between the plates for this capacitor is d=ϵ0AC=(8.85×10−12 C2/N⋅m2)5.86×10−4 m21.97×10−12 F=0.00263 m=2.63 mm
A capacitor is connected to a 9 V battery and acquires a charge Q. What is the charge on the capacitor if it is connected instead to an 18 V battery? Q 2Q 4Q Q/2
2Q The charge on a capacitor is directly proportional to the voltage across it (Q = C∆V). Doubling the voltage doubles the charge.
Which of the following statements are true? Check all that apply. The internal resistance of a battery decreases with decreasing temperature. A battery does work on electric charges to bring them to a position of higher electric potential energy so that they can flow through a circuit to a lower potential energy. A battery is a device that produces electricity by transforming chemical energy into electrical energy. The potential difference between the terminals of a battery, when no current flows to an external circuit, is referred to as the terminal voltage.
A battery does work on electric charges to bring them to a position of higher electric potential energy so that they can flow through a circuit to a lower potential energy. A battery is a device that produces electricity by transforming chemical energy into electrical energy.
Which of the following statements are true? Check all that apply. A capacitor is a device that stores electric potential energy and electric charge. A capacitor consists of a single sheet of a conducting material placed in contact with an insulating material. The electric field between the plates of a parallel-plate capacitor is uniform. The capacitance of a capacitor depends upon its structure.
A capacitor is a device that stores electric potential energy and electric charge. The electric field between the plates of a parallel-plate capacitor is uniform. The capacitance of a capacitor depends upon its structure.
Which of the following statements are true? Check all that apply. A voltmeter is used to measure voltage . An ammeter has a large internal resistance. An ammeter is used to measure current. An ammeter must be placed in parallel with a resistor to measure the current through the resistor. A voltmeter must be placed in parallel with a resistor to measure the voltage across the resistor. A voltmeter has a small internal resistance.
A voltmeter is used to measure voltage An ammeter is used to measure current. A voltmeter must be placed in parallel with a resistor to measure the voltage across the resistor.
A solid conducting sphere is placed in an external uniform electric field. With regard to the electric field on the sphere's interior, which statement is correct? A> There is no electric field on the interior of the conducting sphere. B> The interior field points in a direction parallel to the exterior field. C> The interior field points in a direction perpendicular to the exterior field. D> The interior field points in a direction opposite to the exterior field.
A> There is no electric field on the interior of the conducting sphere.
Which of the following statements are true? Check all that apply. Kirchhoff's loop rule is based on the conservation of charge. At any junction point in a circuit, the sum of all the currents entering the junction must equal the sum of all the currents leaving the junction. The sum of the changes in potential around any closed loop of a circuit must equal zero. Kirchhoff's junction rule is based on the conservation of energy.
At any junction point in a circuit, the sum of all the currents entering the junction must equal the sum of all the currents leaving the junction. The sum of the changes in potential around any closed loop of a circuit must equal zero.
The electric potential at a certain distance from a point charge can be represented by V. What is the value of the electric potential at twice the distance from the point charge? At twice the distance, the electric potential is 2V. At twice the distance, the electric potential remains V. At twice the distance, the electric potential is 4V. At twice the distance, the electric potential is V/4. At twice the distance, the electric potential is V/2.
At twice the distance, the electric potential is V/2
Gaussian surfaces A and B enclose the same positive point charge. The area of surface A is two times larger than that of surface B. How does the total electric flux through the two surfaces compare? The total electric flux through surface B is four times larger than that through surface A. The total electric flux through the two surfaces is equal. a. The total electric flux through surface B is eight times larger than that through surface A. b. The total electric flux through surface A is eight times larger than that through surface B. c. The total electric flux through surface A is four times larger than that through surface B.
B. The total electric flux through the two surfaces is equal.
A POSITIVE charge moves in a direction opposite to that of an electric field. What happens to the energy associated with the charge? A> Both the electric potential energy and the kinetic energy of the charge increase. B> The electric potential energy of the charge increases, and the kinetic energy decreases. C> Both the electric potential energy and the kinetic energy of the charge decrease. D. The electric potential energy of the charge decreases, and the kinetic energy increases.
B> The electric potential energy of the charge increases, and the kinetic energy decreases.
A NEGATIVE charge moves in a direction opposite to that of an electric field. What happens to the energy associated with the charge? A>Both the electric potential energy and the kinetic energy of the charge increase. B>The electric potential energy of the charge decreases, and the kinetic energy increases. C>Both the electric potential energy and the kinetic energy of the charge decrease. D>The electric potential energy of the charge increases, and the kinetic energy decreases.
B>The electric potential energy of the charge decreases, and the kinetic energy increases.
A net charge is placed on a hollow conducting sphere. How does the net charge distribute itself? A> The net charge clumps together at some location within the sphere. B>The net charge uniformly distributes itself on the sphere's inner and outer surfaces. C> The net charge uniformly distributes itself on the sphere's outer surface. D> The net charge uniformly distributes itself on the sphere's inner surface. E> The net charge uniformly distributes itself throughout the thickness of the conducting sphere.
C> The net charge uniformly distributes itself on the sphere's outer surface.
Which of the following statements are true? Check all that apply. In a circuit, current is delivered by the positive terminal of a battery, and it is used up by the time it returns to the negative terminal of the battery. Current is the total amount of charge that passes through a conductor's full cross section at any point per unit of time. In order to maintain a steady flow of current in a conductor, a steady force must be maintained on the mobile charges. When an electric field is applied to a conductor, the free electrons move only in the direction opposite the applied electric field. By convention, the direction of a current is taken to be the direction of flow for negative charges.
Current is the total amount of charge that passes through a conductor's full cross section at any point per unit of time. In order to maintain a steady flow of current in a conductor, a steady force must be maintained on the mobile charges.
If the resistivity of copper is less than that of gold at room temperature, which of the following statements must be true? Electrons in gold are more likely to be scattered than electrons in copper at room temperature when they are accelerated by the same electric field. Gold has a higher resistance than copper. There is more current flowing in the gold than in the copper. The sample of gold is thinner than the sample of copper.
Electrons in gold are more likely to be scattered than electrons in copper at room temperature when they are accelerated by the same electric field. Resistivity is a property of the material independent of its shape (dimensions). It is more and more difficult for electrons to travel through the material with a higher resistivity.
Which of the following statements are true? Check all that apply. Good conductors of electricity have larger conductivity values than insulators. A material that obeys Ohm's law reasonably well is called an ohmic conductor or a linear conductor. The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed. The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed. Semiconductors have resistivity values that are larger than those of insulators.
Good conductors of electricity have larger conductivity values than insulators. A material that obeys Ohm's law reasonably well is called an ohmic conductor or a linear conductor. The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed.`
The electric potential at a certain location from a point charge can be represented by V. What is the value of the electric potential at the same location if the strength of the charge is tripled? If you triple the value of the charge, the electric potential remains V. If you triple the value of the charge, the electric potential is V/9. If you triple the value of the charge, the electric potential is 3V If you triple the value of the charge, the electric potential is 9V. If you triple the value of the charge, the electric potential is V/3.
If you triple the value of the charge, the electric potential is 3V
Which of the following will increase the capacitance of a parallel-plate capacitor? Check all that apply. Increasing the separation between the plates will increase the capacitance of a parallel-plate capacitor. Decreasing the area of the plates will increase the capacitance of a parallel-plate capacitor. Increasing the area of the plates will increase the capacitance of a parallel-plate capacitor. Decreasing the separation between the plates will increase the capacitance of a parallel-plate capacitor.
Increasing the area of the plates will increase the capacitance of a parallel-plate capacitor. Decreasing the separation between the plates will increase the capacitance of a parallel-plate capacitor.
Which of the following will increase the resistance of a wire? Check all that apply. Increasing the resistivity of the material the wire is composed of will increase the resistance of the wire. Decreasing the cross-sectional area of the wire will increase the resistance of the wire. Increasing the cross-sectional area of the wire will increase the resistance of the wire. Decreasing the resistivity of the material the wire is composed of will increase the resistance of the wire. Increasing the length of the wire will increase the resistance of the wire. Decreasing the length of the wire will increase the resistance of the wire.
Increasing the resistivity of the material the wire is composed of will increase the resistance of the wire. Decreasing the cross-sectional area of the wire will increase the resistance of the wire. Increasing the length of the wire will increase the resistance of the wire.
Consider three resistors with unequal resistances connected in parallel to a battery. Which of the following statements are true? Check all that apply. The algebraic sum of the currents flowing through each of the three resistors is equal to the current supplied by the battery. The equivalent resistance of the combination of resistors is less than the resistance of any one of the three resistors. The equivalent resistance of the combination of resistors is greater than the resistance of any one of the three resistors. The algebraic sum of the voltages across the three resistors is equal to the voltage supplied by the battery. The current flowing through each of the resistors is the same and is equal to the current supplied by the battery. The voltage across each of the resistors is the same and is equal in magnitude to the voltage of the battery
The algebraic sum of the currents flowing through each of the three resistors is equal to the current supplied by the battery. The equivalent resistance of the combination of resistors is less than the resistance of any one of the three resistors. The voltage across each of the resistors is the same and is equal in magnitude to the voltage of the battery
The plates of a parallel-plate capacitor are maintained with a constant voltage by a battery as they are pushed together, without touching. How is the amount of charge on the plates affected during this process? The amount of charge on the plates becomes zero. The amount of charge on the plates increases during this process. The amount of charge remains constant. The amount of charge on the plates decreases during this process.
The amount of charge on the plates increases during this process.
If a dielectric material, such as Teflon®, is placed between the plates of a parallel-plate capacitor without altering the structure of the capacitor, how is the capacitance affected? The capacitance increases because of the insertion of the Teflon®. The capacitance decreases because of the insertion of the Teflon®. The capacitance becomes zero after the insertion of the Teflon®. The capacitance is not altered, because the structure remains unchanged. The capacitance becomes infinite after the insertion of the Teflon®.
The capacitance increases because of the insertion of the Teflon®.
A 1.97-pF capacitor is connected to a 9.0-V battery and fully charged. How many electrons did the battery transfer from one capacitor plate to the other? 1.77 × 10-11 3.52 × 1029 1.11 × 108 1.37 × 106
The charge on a capacitor is Q=CΔV, where C is the capacitance and ΔV is the voltage across the capacitor. When the capacitor is fully charged, ΔV=ΔVbat=9.0 V. The charge, Q, is equal to the number of electrons that are transferred from one plate to the other times the charge on each electron: Q = Ne. So the number of electrons transferred is N=CΔVe=(1.97×10−12 F)(9.0 V)1.602×10−19 C=1.11×108.
Consider two capacitors with unequal capacitance connected in series to a battery. Which of the following statements are true? Check all that apply. The charge stored on each of the capacitors is the same. The algebraic sum of the voltages across the two capacitors is equal to the voltage supplied by the battery. The voltage across each of the capacitors is the same. The equivalent capacitance of the combination of the two capacitors is less than the capacitance of either of the capacitors. The equivalent capacitance of the combination of the two capacitors is greater than the capacitance of either of the capacitors. The sum of the charges stored on each capacitor is equal to the charge supplied by the battery.
The charge stored on each of the capacitors is the same. The algebraic sum of the voltages across the two capacitors is equal to the voltage supplied by the battery. The equivalent capacitance of the combination of the two capacitors is less than the capacitance of either of the capacitors.
If the voltage across a circuit of constant resistance is doubled, how is the current in the circuit affected? The current is reduced by a factor of 2. The current is doubled. The current is reduced by a factor of 4. The current is quadrupled. The current remains constant.
The current is doubled.
A dielectric material, such as Teflon®, is placed between the plates of a parallel-plate capacitor without altering the structure of the capacitor. The charge on the capacitor is held fixed. How is the electric field between the plates of the capacitor affected? The electric field decreases because of the insertion of the Teflon®. The electric field is not altered, because the structure remains unchanged. The electric field becomes zero after the insertion of the Teflon®. The electric field increases because of the insertion of the Teflon®. The electric field becomes infinite because of the insertion of the Teflon®.
The electric field decreases because of the insertion of the Teflon®.
In the figure, a uniform electric field is shown passing through a flat area A. In (a), the surface of area A is perpendicular to the electric field. In (b), the surface is tilted by an angle θ with respect to the electric field. In (c), the surface is parallel to the electric field. In which orientation is the electric flux through the surface the equal to zero?
The electric flux is the zero through the surface shown in (c). where the surface is parallel to the electric field
A parallel-plate capacitor connected to a battery becomes fully charged. After the capacitor from the battery is disconnected, the separation between the plates of the capacitor is doubled in such a way that no charge leaks off. How is the energy stored in the capacitor affected? The energy stored in the capacitor is decreased to one-half of its original value. The energy stored in the capacitor remains constant. The energy stored in the capacitor doubles its original value. The energy stored in the capacitor is decreased to one-fourth of its original value. The energy stored in the capacitor quadruples its original value.
The energy stored in the capacitor doubles its original value.
The voltage applied across a given parallel-plate capacitor is doubled. How is the energy stored in the capacitor affected? The energy stored in the capacitor is decreased to one-fourth of its original value. The energy stored in the capacitor doubles its original value. The energy stored in the capacitor remains constant. The energy stored in the capacitor is decreased to one-half of its original value. The energy stored in the capacitor quadruples its original value.
The energy stored in the capacitor quadruples its original value.
Consider three resistors with unequal resistances connected in series to a battery. Which of the following statements are true? Check all that apply. The equivalent resistance of the combination of resistors is less than the resistance of any one of the three resistors. The equivalent resistance of the combination of resistors is greater than the resistance of any one of the three resistors. The algebraic sum of the currents flowing through each of the three resistors is equal to the current supplied by the battery. The voltage across each of the resistors is the same and is equal in magnitude to the voltage of the battery. The algebraic sum of the voltages across the three resistors is equal to the voltage supplied by the battery. The current flowing through each of the resistors is the same and is equal to the current supplied by the battery.
The equivalent resistance of the combination of resistors is greater than the resistance of any one of the three resistors. The algebraic sum of the voltages across the three resistors is equal to the voltage supplied by the battery. The current flowing through each of the resistors is the same and is equal to the current supplied by the battery.
Four +2 μC charges are placed at the positions (10 cm, 0 cm), (−10 cm, 0 cm), (0 cm, 10 cm), and (0 cm, −10 cm) such that they form a diamond shape centered on the origin. A charge of +5 μC is placed at the origin. If the force between a +2 μC and a +5 μC charge separated by 10 cm has a magnitude of 9 N, which of the following can we say about the force on the +5 μC charge at the origin in this case?
The force on the charge at the origin is 0. Many times it is possible to find the force on a charge due to other charges without doing any calculations by simply considering the symmetry of the arrangement of charges. In this case, there is mirror symmetry across both the x axis and the y axis so there can be no net push or pull in either of those directions.
Which of the following statements are true? Check all that apply. After the space between the two conductors in a capacitor is filled with a dielectric material, the capacitance of the capacitor decreases. The insertion of a dielectric material between the two conductors in a capacitor allows a higher voltage to be applied to the capacitor. The insertion of a dielectric material between the two conductors in a capacitor allows the plates of the capacitor to be placed closer together without touching. Dielectrics allow electric charge to flow as easily as they do in air.
The insertion of a dielectric material between the two conductors in a capacitor allows a higher voltage to be applied to the capacitor. The insertion of a dielectric material between the two conductors in a capacitor allows the plates of the capacitor to be placed closer together without touching.
A parallel-plate capacitor is connected to a battery. After it becomes charged, the capacitor is disconnected from the battery and the plate separation is increased. What happens to the potential difference between the plates? The potential difference between the plates stays the same. More information is needed to answer this question. The potential difference between the plates increases. The potential difference between the plates decreases.
The potential difference between the plates increases. When the capacitor is disconnected from the battery, the charge on the plates cannot change (Q = C∆V). Increasing the distance between the plates decreases the capacitance (C =ϵ0A/d). Therefore, the potential difference must increase.
A positive charge moves in the direction of an electric field. Which of the following statements are true? Check all that apply. The potential energy associated with the charge increases. The potential energy associated with the charge decreases. The amount of work done on the charge cannot be determined without additional information. The electric field does negative work on the charge. The electric field does positive work on the charge. The electric field does not do any work on the charge.
The potential energy associated with the charge decreases. The amount of work done on the charge cannot be determined without additional information. The electric field does positive work on the charge.
A negative charge moves in the direction of an electric field. Which of the following statements are true? Check all that apply. The potential energy associated with the charge increases. The electric field does not do any work on the charge. The potential energy associated with the charge decreases. The amount of work done on the charge cannot be determined without additional information. The electric field does positive work on the charge. The electric field does negative work on the charge.
The potential energy associated with the charge increases. The amount of work done on the charge cannot be determined without additional information. The electric field does negative work on the charge.
A circuit maintains a constant resistance. If the current in the circuit is doubled, what is the effect on the power dissipated by the circuit? The power dissipated is quadrupled. The power dissipated is doubled. The power dissipated is reduced by a factor of 2. The power dissipated remains constant. The power dissipated is reduced by a factor of 4.
The power dissipated is quadrupled
A constant voltage is applied across a circuit. If the resistance in the circuit is doubled, what is the effect on the power dissipated by the circuit? The power dissipated is doubled. The power dissipated is reduced by a factor of 4. The power dissipated is quadrupled. The power dissipated remains constant. The power dissipated is reduced by a factor of 2.
The power dissipated is reduced by a factor of 2.
As additional resistors are connected in series to a constant voltage source, how is the power supplied by the source affected? The power supplied by the sources remains constant. The power supplied by the source increases. The effect on the power supplied by the source cannot be determined without knowing the voltage of the source. The power supplied by the source decreases
The power supplied by the source decreases
As additional resistors are connected in parallel to a constant voltage source, how is the power supplied by the source affected? The power supplied by the sources remains constant. The power supplied by the source decreases. The effect on the power supplied by the source cannot be determined without knowing the voltage of the source. The power supplied by the source increases.
The power supplied by the source increases.
What happens to the resistance of most common metals as the temperature of the metal increases? The resistance remains constant as temperature increases. The resistance increases as temperature increases. Whether resistance increases or decreases as temperature increases depends on the type of metal. The resistance decreases as temperature increases.
The resistance remains constant as temperature increases.
The plates of a parallel-plate capacitor are maintained with a constant voltage by a battery as they are pulled apart. How is the strength of the electric field affected during this process? The electric field between the plates becomes infinite. The strength of the electric field decreases during this process. The strength of the electric field remains constant. The electric field between the plates becomes zero. The strength of the electric field increases during this process.
The strength of the electric field decreases during this process.
How do the resistances of two conducting wires compare if they have the same length, but one is twice the radius of the other? The thicker wire has one-fourth the resistance of the thinner wire. The thicker wire has twice the resistance of the thinner wire. The resistance is the same in both wires. The thicker wire has half the resistance of the thinner wire.
The thicker wire has one-fourth the resistance of the thinner wire. A thicker wire will allow more current to flow with the same voltage difference driving it, because the resistance is inversely proportional to the area of the wire.
Consider two capacitors with unequal capacitance connected in parallel to a battery. Which of the following statements are true? Check all that apply. The sum of the charge stored on each capacitor is equal to the charge supplied by the battery. The equivalent capacitance of the combination is greater than the capacitance of either of the capacitors. The equivalent capacitance of the combination is less than the capacitance of either of the capacitors. The algebraic sum of the voltages across the two capacitors is equal to the voltage supplied by the battery. The voltage across each of the capacitors is the same. The charge stored on each of the capacitors is the same.
The voltage across each of the capacitors is the same. The equivalent capacitance of the combination is greater than the capacitance of either of the capacitors. The sum of the charge stored on each capacitor is equal to the charge supplied by the battery.
A resistor, capacitor, and switch are all connected in series to an ideal battery of constant terminal voltage. Initially, the switch is open. What is the voltage across the resistor and the capacitor at the moment the switch is closed? The voltage across both the resistor and the capacitor is zero. The voltage across both the resistor and the capacitor is equal to the terminal voltage of the battery. The voltage across both the resistor and the capacitor is equal to one-half of the terminal voltage of the battery. The voltage across the resistor is equal to the terminal voltage of the battery, and the voltage across the capacitor is zero. The voltage across the resistor is zero, and the voltage across the capacitor is equal to the terminal voltage of the battery.
The voltage across the resistor is equal to the terminal voltage of the battery, and the voltage across the capacitor is zero.
A resistor and a capacitor are connected in series to an ideal battery of constant terminal voltage. When the system reaches its steady state, what is the voltage across the resistor and the capacitor? The voltage across both the resistor and the capacitor is equal to the terminal voltage of the battery. The voltage across both the resistor and the capacitor is zero. The voltage across the resistor is equal to the terminal voltage of the battery, and the voltage across the capacitor is zero. The voltage across the resistor is zero, and the voltage across the capacitor is equal to the terminal voltage of the battery. The voltage across both the resistor and the capacitor is equal to one-half of the terminal voltage of the battery.
The voltage across the resistor is zero, and the voltage across the capacitor is equal to the terminal voltage of the battery
A dielectric material, such as Teflon®, is placed between the plates of a parallel-plate capacitor without altering the structure of the capacitor. The charge on the capacitor is held fixed. How is the voltage across the plates of the capacitor affected? The voltage becomes infinite because of the insertion of the Teflon®. The voltage increases because of the insertion of the Teflon®. The voltage is not altered, because the structure remains unchanged. The voltage becomes zero after the insertion of the Teflon®. The voltage decreases because of the insertion of the Teflon®.
The voltage decreases because of the insertion of the Teflon®.
If the resistance in a circuit connected to a constant current is halved, how is the voltage in the circuit affected? The voltage is reduced by a factor of 4. The voltage is doubled. The voltage is quadrupled. The voltage is reduced by a factor of 2. The voltage remains constant.
The voltage is reduced by a factor of 2.
Which of the following statements are true? Check all that apply. When all charges are at rest, the surface of a conductor is always an equipotential surface. An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point. The potential energy of a test charge increases as it moves along an equipotential surface. Electric field lines and equipotential surfaces are always mutually perpendicular. The potential energy of a test charge decreases as it moves along an equipotential surface.
When all charges are at rest, the surface of a conductor is always an equipotential surface. An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point. Electric field lines and equipotential surfaces are always mutually perpendicular.
Consider two copper wires with the same cross-sectional area. Wire A is twice as long as wire B. How do the resistivities and resistances of the two wires compare? Check all that apply. Wire A has twice the resistivity of wire B. Wire A and wire B have the same resistivity. Wire B has twice the resistance of wire A. Wire A and wire B have the same resistance. Wire A has twice the resistance of wire B. Wire B has twice the resistivity of wire A.
Wire A and wire B have the same resistivity. Wire A has twice the resistance of wire B.
A charge of +0.001 C is 1 m to your right and another charge of +1000 C is 1 m to your left. You are holding a charge of −1 C. Which of the following statements is/are true? Check all that apply. a. The net force on the charge you are holding is to your right. b. The magnitude of the force on the charge you are holding would be the same if it were +1 C instead of −1 C. c. The force on the charge you are holding from the charge on your left is 1,000,000 times as large as the force from the charge on your right. d. Because the charge on the left is so much larger than the one on the right, there is no force from the +0.001 C charge on the charge you are holding.
b. The magnitude of the force on the charge you are holding would be the same if it were +1 C instead of −1 C. c. The force on the charge you are holding from the charge on your left is 1,000,000 times as large as the force from the charge on your right. The magnitude of the force between two charges is proportional to the magnitude of the charges. The direction of the force depends on whether the charges are alike or opposite. Because they are forces, you must find the net force by doing a vector addition of the forces from all the surrounding charges.
A disk with a radius of R is oriented with its normal unit vector at an angle θ with respect to a uniform electric field. Which of the following would result in an increase in the electric flux through the disk? Check all that apply. a. decreasing the strength of the electric field b. increasing the area of the disk c. decreasing the given orientation angle of the disk d. increasing the given orientation angle of the disk, but not exceeding an angle of 90° e. increasing the strength of the electric field f. decreasing the area of the disk
b. increasing the area of the disk c. decreasing the given orientation angle of the disk e. increasing the strength of the electric field
A disk with a radius of R is oriented with its normal unit vector at an angle Θ with respect to a uniform electric field. Which of the following represent the electric flux through the disk? Check all that apply. a. E(πR2)cosϕ b. E(2πR)sinΘ c. E(πR2)sinϕ d. E(πR2)cosΘ e.E(πR2)sinΘ f. E(2πR)cosΘ
c. E(πR2)sinϕ d. E(πR2)cosΘ
Which of the following would double the amount of current flowing through a piece of metal wire? Quarter the voltage across it. Halve the voltage across it. Double the voltage across it. Quadruple the voltage across it.
double the voltage across it According to Ohm's law, the current is proportional to the voltage when the resistance stays the same.
