PHY 2185: iClicker Review for Final Exam
b) electrons
J.J. Thompson discovered which one of the following with his crossed fields experiment? a) magnetic field b) electrons c) magnetic monopoles d) protons e) neutrons
d) Thompson
Which of the following scientists is credited with the discovery of the electron? a) Planck b) Curie c) Maxwell d) Thompson e) Fermi
a) 0.083 s
A 150-Ω resistor and a 0.80-mH inductor are used in an LR circuit. If the initial current in the circuit is 2.0 A when a switch is thrown that allows the current in the circuit to decay, at what time will the current be 1.0 A? a) 0.083 s b) 0.12 s c) 0.48 s d) 0.80 s e) 1.3 s
b) 0.031 V
A balloon has an initial radius of 0.075 m. A circle is painted on the balloon using silver metal paint. When the paint dries, the circle is a very good electrical conductor. With the balloon oriented such that a 1.5-T magnetic field is oriented perpendicular to the plane of the circle, air is blown into the balloon so that it expands uniformly. The silver circle expands to a radius 0.125 m in 1.5 s. Determine the induced emf for this silver circle during this period of expansion. a) 0.021 V b) 0.031 V c) 0.047 V d) 0.058 V e) 0.075 V
e) The stored energy of capacitor B is four times that of capacitor A.
A battery charges capacitor A until the potential difference between the two conductors of the capacitor is V. A second, identical capacitor, labeled B, is charged by another battery until the potential difference of capacitor B is 2V. How does the stored energy of capacitor B compare to that of capacitor A? a) The stored energy in both capacitors is the same since the capacitance of both is the same. b) The stored energy of capacitor B is one-fourth that of capacitor A. c) The stored energy of capacitor B is one-half that of capacitor A. d) The stored energy of capacitor B is twice that of capacitor A. e) The stored energy of capacitor B is four times that of capacitor A.
c) in the direction that is perpendicular to both the magnetic field and the velocity
A charged particle is moving in a magnetic field. What is the direction of the force on the particle due to the magnetic field? a) in the direction of the magnetic field b) in the direction opposite to which the particle is moving c) in the direction that is perpendicular to both the magnetic field and the velocity d) in the same plane as the magnetic field and the velocity, but not in either of those two directions e) in the direction of motion
c) a long time after the switch is closed
A circuit contains a battery, a switch, an inductor, and a resistor connected in series. Initially, the switch is open. In which one of the following intervals does the energy stored in the inductor have the largest value? a) before the switch is closed b) immediately after the switch is closed when the current in the circuit is increasing c) a long time after the switch is closed
e) None of the above answers is correct
A conducting shell with an outer radius of 2.5 cm and an inner radius of 1.5 cm has an excess charge of 1.5 × 10⁻⁷ C. What is the surface charge density on the inner wall of the shell? a) 1.5 × 10⁻⁹ C/m² b) 2.9 × 10⁻¹⁰ C/m² c) 4.8 × 10⁻¹⁰ C/m² d) 8.5 × 10⁻⁹ C/m² e) None of the above answers is correct
a) positive value.
A conducting sphere is connected via a wire to the ground. For a very short time, electrons move from the ground to the sphere. Then, no more electrons move to the sphere. Complete the following sentence: Before the wire was connected, the sphere's electric potential had a a) positive value. b) negative value. c) value that could have been either positive or negative. d) value equal to zero volts.
e) vertically downward
A long wire carries a current toward the east in a magnetic field that is directed due south. What is the direction of the magnetic force on the wire? a) west b) north c) east d) vertically upward e) vertically downward
a) west
A long wire carries a current toward the north in a magnetic field that is directed vertically downward. What is the direction of the magnetic force on the wire? a) west b) north c) east d) vertically upward e) vertically downward
b) 0° and 180°
A magnetic dipole has two stable orientations in a magnetic field. At what two angles relative to the magnetic field direction are these orientations? a) 0° and 90° b) 0° and 180° c) 90° and 270° d) 45° and 135° e) 45° and 90°
d) The magnetic field is parallel to the direction of the current in the wire
A magnetic field is generated by a current-carrying wire. Which one of the following statements concerning this situation is false? a) The magnitude of this magnetic field decreases with increasing distance away from the wire. b) A right-hand rule is useful for determining the direction of the magnetic field at a particular location. c) The magnitude of the magnetic field is directly proportional to the magnitude of the current. d) The magnetic field is parallel to the direction of the current in the wire.
c) It will follow a straight line path in the same direction as it was initially traveling.
A negatively-charged particle is slowly moving as it enters a region that has a constant magnetic field. If the velocity of the particle is initially parallel to the magnetic field, what will be the subsequent motion of the particle? a) It will follow a helical path around the magnetic field lines. b) It will follow a circular path in the plane perpendicular to the magnetic field lines. c) It will follow a straight line path in the same direction as it was initially traveling. d) It will follow a circular path in a plane parallel to the magnetic field lines. e) It is impossible to predict the path the particle will follow.
b) It will follow a circular path in the plane perpendicular to the magnetic field lines.
A negatively-charged particle is slowly moving as it enters a region that has a constant magnetic field. If the velocity of the particle is initially perpendicular to the magnetic field, what will be the subsequent motion of the particle? a) It will follow a helical path around the magnetic field lines. b) It will follow a circular path in the plane perpendicular to the magnetic field lines. c) It will follow a straight line path in the same direction as it was initially traveling. d) It will follow a circular path in a plane parallel to the magnetic field lines. e) It is impossible to predict the path the particle will follow.
a) UA > UB
A positively-charged particle is held at point A between two parallel metal plates. The plate on the left has a net positive charge +q and the plate on the right has a net negative charge -q. The particle is then moved right, to point B. How does the electric potential energy at point A compare with that at point B? a) UA > UB b) UA = UB c) UA < UB d) UA > UB or UA < UB depending on the actual distances from the points to the plates.
e) all of the above
A rigid, conductive loop is falling through a uniform magnetic field that is perpendicular to the plane of the loop. Initially, the loop is completely within the field, but then it falls into a region where no magnetic field is present. Which one of the following quantities varies during the fall? a) the magnetic field penetrating the loop b) the area of the loop penetrated by the magnetic field c) the magnetic flux d) the current in the loop e) all of the above
a) at infinity
A sphere has a radius R and a total charge Q uniformly distributed throughout its volume. Where is the electric potential of the sphere a minimum? a) at infinity b) at the surface of the sphere, r = R c) R/2 < r < R d) 0 < r < R/2 e) at the center of the sphere, r = 0
a) under all conditions
A spherical Gaussian surface of radius R is surrounding a particle with a net charge q. If the spherical Gaussian surface is replaced by a cube, under what conditions would the electric flux through the sides of the cube be the same as through the spherical surface? a) under all conditions b) if the sides of the cube are of length R c) if the sides of the cube are of length 2R d) if the diagonals of the cube are of length 2R e) under no conditions
c) -1.6 × 10⁻⁸ C/m²
A spherical shell has an outer radius of 0.10 m and an inner radius of 0.040 cm. Within the shell is a charge q = -2.0 × 10⁻⁹ C. What is the surface charge density on the outer surface of the shell? a) -2.0 × 10⁻⁹ C/m² b) -9.9 × 10⁻⁹ C/m² c) -1.6 × 10⁻⁸ C/m² d) -3.8 × 10⁻¹⁰ C/m² e) -8.0 × 10⁻⁸ C/m²
e) 4.8 × 10⁷ N/C
A straight, copper wire has a length of 0.50 m and an excess charge of -1.0 × 10⁻⁵ C distributed uniformly along its length. Find the magnitude of the electric field at a point located 7.5 × 10⁻³ m from the midpoint of the wire. a) 1.9 × 10¹⁰ N/C b) 7.3 × 10⁸ N/C c) 6.1 × 10¹³ N/C d) 1.5 × 10⁶ N/C e) 4.8 × 10⁷ N/C
a) 2.89 x 10⁵ N/C, radially inward
A total charge of -6.50 µC is uniformly distributed within a sphere that has a radius of 0.150 m. What is the magnitude and direction of the electric field at 0.300 m from the surface of the sphere? a) 2.89 x 10⁵ N/C, radially inward b) 9.38 x 10⁵ N/C, radially outward c) 1.30 x 10⁶ N/C, radially inward d) 6.49 x 10⁵ N/C, radially outward e) 4.69 x 10⁵ N/C, radially inward
a) The electric potential will decrease with increasing y.
A uniform electric field is directed parallel to the +y axis. If a positive test charge begins at the origin and moves upward along the y axis, how does the electric potential vary, if at all? a) The electric potential will decrease with increasing y. b) The electric potential will increase with increasing y. c) The electric potential will remain constant with increasing y. d) Too little information is given to answer this question.
a) The subsequent motion of the electron will be the same as if there were an electric field directed due west and no magnetic field present.
An electron is traveling due south when it enters a uniform magnetic field directed due west. Which of the following statements concerning this situation is false? a) The subsequent motion of the electron will be the same as if there were an electric field directed due west and no magnetic field present. b) The electron will follow a curved path. c) The direction of the magnetic force on the electron will vary with time. d) The magnitude of the magnetic force will be constant with time. e) The direction of the magnetic field and the direction of the magnetic force on the electron are perpendicular to one another.
e) in the direction that is perpendicular to both the wire and to the radial direction
At a distance R from a current carrying wire, what is the direction of the magnetic field relative to the wire? a) radially toward the wire b) radially away from the wire c) parallel to the wire d) in the direction opposite to that of the current e) in the direction that is perpendicular to both the wire and to the radial direction
b) 1.4 cm
At a distance of one centimeter from an electron, the electric field strength has a value E. At what distance is the electric field strength equal to E/2? a) 0.5 cm b) 1.4 cm c) 2.0 cm d) 3.2 cm e) 4.0 cm
e) 180°
At what orientation angle relative to the magnetic field direction does the magnetic potential energy of a magnetic dipole have its largest value? a) 0° b) 45° c) 90° d) 135° e) 180°
c) 90°
At what orientation angle relative to the magnetic field direction does the torque of a magnetic dipole have its largest value? a) 0° b) 45° c) 90° d) 135° e) 180°
b) The current in circuit B decreases more slowly than that for circuit A since the inductor acts to maintain the current in the circuit.
Circuit A contains a battery, a switch, and a resistor connected in series. Circuit B contains a battery, a switch, an inductor, and a resistor connected in series. Initially, the switch is closed in both circuits. How does the behavior of the current in circuit B compare with that in circuit A as both switches are opened at the same time? a) The current in both circuits decreases at the same rate because inductors do not affect the current in a circuit. b) The current in circuit B decreases more slowly than that for circuit A since the inductor acts to maintain the current in the circuit. c) The current in circuit B decreases more quickly than that for circuit A since the inductor increases the current in the circuit as its stored energy is released. d) The behavior of the current in the circuit depends on the inductance of the inductor. If the inductance is small, the current will decrease rapidly; and if the inductance is large, the current will increase for a short time before decreasing.
a) remain at rest.
Complete the following sentence: When a positively-charged particle is released from rest in a region that has a magnetic field directed due east, the particle will a) remain at rest. b) be accelerated due east. c) be accelerated due north. d) be accelerated upward. e) be accelerated downward.
d) the electric field lines are perpendicular to the surface.
Complete the following statement: Along an equipotential surface, a) the magnitude of the electric field is constant. b) the electric field lines are parallel to the surface. c) the direction of the magnetic field is constant. d) the electric field lines are perpendicular to the surface. e) both the magnitude and direction of the electric field is constant
c) equals the sum of the potential rises.
Complete the following statement: Around any closed-circuit loop, the sum of the potential drops a) dramatically with the addition of each resistor. b) in each loop is the same. c) equals the sum of the potential rises. d) equals the emf of the battery. e) increases with the addition of each resistor.
a) equals the sum of the magnitudes of the currents directed out of the junction.
Complete the following statement: The sum of the magnitudes of the currents directed into a junction a) equals the sum of the magnitudes of the currents directed out of the junction. b) is less than the total current directed out of the junction. c) equals the current that is directed along one of the lines out of the junction. d) is divided equally among the number of lines directed out of the junction. e) is greater than the total current directed out of the junction.
e) 1 and 3 only
Consider the following quantities: (1) current, (2) resistance, (3) coil area, (4) wire cross-sectional area, and (5) magnetic field. Upon which of the quantities is the magnetic dipole moment of a current carrying coil dependent? a) 1 and 5 only b) 1 and 2 only c) 2 and 3 only d) 1, 3, 4, and 5 e) 1 and 3 only
d) 2, 3, and 4 only
Consider the following quantities: (1) mass, (2) velocity, (3) charge, and (4) magnetic field strength. Upon which of these quantities is the force on a charged particle moving in a magnetic field dependent? a) 1 and 4 only b) 2 and 3 only c) 1, 3, and 4 only d) 2, 3, and 4 only e) 1, 2, and 3 only
c) r = R, at the surface of the wire
Consider the magnetic field generated by a long, straight current-carrying wire of radius R. At which of the following locations is the magnetic energy density of the wire the largest? a) r = 0, at the center of the wire b) 0 < r < R c) r = R, at the surface of the wire d) R < r < 2R e) The magnetic field density will be the same everywhere.
a) The total electric potential at the origin is equal to -5kq/2r.
Consider the two charged particles. One charge located on the y axis has a value -2q and is located at a distance r from the origin, point O. The other charge has a value -q and is located at a distance 2r from the origin along the x axis. Which one of the following statements concerning the electric potential at the origin is true? a) The total electric potential at the origin is equal to -5kq/2r. b) The total electric potential at the origin is equal to zero volts. c) The total electric potential at the origin is equal to -2kq/r. d) The total electric potential at the origin cannot be calculated since the charges are on different axes. e) The total electric potential at the origin is equal to -3kq/2r.
b) The electrostatic potential of the larger sphere is at a lower potential than the smaller sphere.
Consider two isolated conductive metal spheres. Each carries the same amount of excess charge Q, but one has a radius that is five times greater than the other. How does the electrostatic potential of the two spheres compare? a) The electrostatic potential of the larger sphere is at a higher potential than the smaller sphere. b) The electrostatic potential of the larger sphere is at a lower potential than the smaller sphere. c) The electrostatic potential of the larger sphere is at the same potential than the smaller sphere.
b) The two wires will repel each other, even if no external magnetic field is applied to the wires.
Consider two parallel wires carrying current in opposite directions. Which one of the following statements to true concerning this situation? a) The two wires will attract each other, even if no external magnetic field is applied to the wires. b) The two wires will repel each other, even if no external magnetic field is applied to the wires. c) The two wires will attract each other, only if an external magnetic field is applied to the wires. d) The two wires will repel each other, only if an external magnetic field is applied to the wires. e) The wires will be neither attracted nor repelled from each other when no external magnetic field is applied to the wires.
a) The two wires will attract each other, even if no external magnetic field is applied to the wires.
Consider two parallel wires carrying current in the same direction. Which one of the following statements to true concerning this situation? a) The two wires will attract each other, even if no external magnetic field is applied to the wires. b) The two wires will repel each other, even if no external magnetic field is applied to the wires. c) The two wires will attract each other, only if an external magnetic field is applied to the wires. d) The two wires will repel each other, only if an external magnetic field is applied to the wires. e) The wires will be neither attracted nor repelled from each other when no external magnetic field is applied to the wires.
b) A test charge placed at the intersection of two electric field lines would experience a force in two different directions.
Consider what would happen if electric field lines could cross each other. What would it mean if two electric field lines were to cross? a) A test charge placed at the intersection of two electric field lines would be torn apart and travel in two different directions. b) A test charge placed at the intersection of two electric field lines would experience a force in two different directions. c) A positive test charge placed at the intersection of two electric field lines would follow one of the lines and a negative test charge would follow the other line. d) The electric field at the intersection point would be infinitely large. e) The electric field at the intersection point would be zero.
c) the amount of charge on the conductors
For a cylindrical capacitor, the capacitance does not depend on which of the following values? a) the permittivity constant b) the radius of the inner conductor c) the amount of charge on the conductors d) the radius of the outer conductor e) the length of the cylinder
b) 4kQ/a
Four point charges are individually brought from infinity and placed at the corners of a square as shown in the figure. Each charge has the identical value +Q. The length of the diagonal of the square is 2a. What is the electric potential at the center of the square? a) kQ/a b) 4kQ/a c) 2kQ/a d) kQ/4a e) zero volts
a) The two capacitors connected in series have a larger capacitance.
How does the capacitance of two identical capacitors connected in parallel compare to that of one of the capacitors? a) The two capacitors connected in series have a larger capacitance. b) The two capacitors connected in series have the same capacitance. c) The two capacitors connected in series have a smaller capacitance.
c) The two capacitors connected in series have a smaller capacitance.
How does the capacitance of two identical capacitors connected in series compare to that of one of the capacitors? a) The two capacitors connected in series have a larger capacitance. b) The two capacitors connected in series have the same capacitance. c) The two capacitors connected in series have a smaller capacitance.
a) The direction within the dielectric is opposite to that due to the plates.
How does the direction of the electric field within a dielectric inserted between the plates of a parallel plate capacitor compare to the direction of the electric field due to the charged plates? a) The direction within the dielectric is opposite to that due to the plates. b) The direction within the dielectric is parallel to that due to the plates. c) The direction within the dielectric is perpendicular to that due to the plates. d) There is no electric field inside the dielectric.
b) Break the circuit into smaller parts and find an equivalent resistance for each part. Then continue this process until all of the parts are added together correctly either in series or parallel until a single equivalent resistance is found.
In analyzing circuits in which resistors are wired partially in series and partially in parallel, which one of the following statements describes the preferred approach to take to determine the equivalent resistance in the circuit? a) Find the sum of all the resistors. This is the equivalent resistance for the circuit. b) Break the circuit into smaller parts and find an equivalent resistance for each part. Then continue this process until all of the parts are added together correctly either in series or parallel until a single equivalent resistance is found. c) All together all of the resistors in series, ignoring any wired in parallel as they do not significantly add to the equivalent resistance of the circuit. The sum of the resistors in series is the equivalent resistance. d) All together all of the resistors in parallel, ignoring any wired in series as they do not significantly add to the equivalent resistance of the circuit. The sum of the resistors in parallel is the equivalent resistance.
d) -iR
In analyzing electric circuits containing a battery and at least one resistor, what is the change in potential across a resistor as one moves through it in the direction of the current? a) +i²R b) -i²R c) +iR d) -iR e) zero
a) +ε
In analyzing electric circuits containing an ideal emf device that has an emf ε and at least one resistor, what is the change in potential across the emf device as one moves through it in the direction of the emf arrow? a) +ε b) -ε c) +ε / R d) -ε / R e) zero
c) Electrons in a beam are moving due south.
In which one of the following situations does a conventional electric current flow due north? a) Protons in a beam are moving due south. b) A water molecule is moving due north. c) Electrons in a beam are moving due south. d) Electrons in a wire connected to a battery are moving from south to north.
e) 3R
One end of resistor A is connected to the positive terminal of a battery and the other end is connected to resistor B. The opposite end of resistor B is connected to the negative terminal of the battery. If resistor A has resistance R and B has a resistance 2R, what is the equivalent resistance of this circuit? a) R b) 3R/2 c) 2R d) 2R/3 e) 3R
c) The algebraic sum of the two electric potentials is determined at a distance r/2 from each of the charges, making sure to include the signs of the charges.
Point charge A is located at point A and point charge B is at point B. Points A and B are separated by a distance r. To determine the electric potential at the mid-point along a line between points A and B, which of the following mathematical approaches is correct? a) The electric potential due to each charge is determined at a distance r/2 from each of the charges and an average is taken of the two values. b) The vector sum of the two electric potentials determines the total electric potential at a distance r/2 from each of the charges. c) The algebraic sum of the two electric potentials is determined at a distance r/2 from each of the charges, making sure to include the signs of the charges. d) The difference in the absolute value (the sign of the charges does not enter into the calculation) of the two electric potentials is determined at a distance r/2 from each of the charges.
e) The particle will accelerate in the direction of point C.
Points A, B, and C lie along a line from left to right, respectively. Point B is at a lower electric potential than point A. Point C is at a lower electric potential than point B. Which one of the following statements best describes the subsequent motion, if any, of a positively-charged particle released from rest at point B? a) The particle will move at constant velocity in the direction of point A. b) The particle will move at constant velocity in the direction of point C. c) The particle will remain at rest. d) The particle will accelerate in the direction of point A. e) The particle will accelerate in the direction of point C.
c) µA = µC > µB > µD
Solenoid A has n turns per unit length and carries a current 4i. Solenoid B has 3n turns per unit length and carries a current i. Solenoid C has 2n turns per unit length and carries a current 2i. Solenoid D has n turns per unit length and carries a current 2i. Which of the following expressions correctly expresses the relative energy density of these solenoids? a) µA > µD > µB > µC b) µB = µD > µA > µC c) µA = µC > µB > µD d) µC > µA > µB > µD e) µD > µB > µC = µA
b) The magnetic field after the stretching is one-half the value it was before stretching.
The coils of a solenoid are stretched so that the length of the solenoid is twice its original length. Assuming the same current is passed though the solenoid before and after it is stretched, how does the magnetic field inside the solenoid change, if at all, as a result of the stretching? a) The magnetic field after the stretching is one-fourth the value it was before stretching. b) The magnetic field after the stretching is one-half the value it was before stretching. c) The magnetic field after the stretching is the same as the value it was before stretching. d) The magnetic field after the stretching is twice the value it was before stretching. e) The magnetic field after the stretching is four times the value it was before stretching.
c) 1.6 × 10²³
The drift speed within a certain conductor is 0.10 mm/s. How many electrons move through a unit cross-sectional area in the circuit each second if the current is 2.5 A? a) 2.5 × 10⁴ b) 1.6 × 10¹⁵ c) 1.6 × 10²³ d) 2.5 × 10²² e) 6.4 × 10²⁸
e) V
The electric potential at the surface of a conducting, spherical shell of radius R is V relative to Earth ground. What is the electric potential at the center of the shell? a) zero volts b) V/R c) V/(4πR)² d) V/2 e) V
b) Replace the wire with one that has a larger radius.
The ends of a wire are connected to the terminals of a battery. For which of the following changes will the resulting current in the circuit have the largest value? a) Replace the wire with one that has a larger resistivity. b) Replace the wire with one that has a larger radius. c) Replace the wire with one that has a longer length.
b) The charge on the plates remains unchanged.
The plates of a parallel plate capacitor are fully charged by connecting it to a battery. An insulator with a dielectric constant κ = 1.0 is then inserted between the plates. What is the effect on the charge on the plates of the insertion of the insulator? a) The charge on the plates increases. b) The charge on the plates remains unchanged. c) The charge on the plates decreases.
b) less than 12 V.
The positive terminal of a battery in a minivan has an electric potential that is a maximum of 12 V higher than the negative terminal. Complete the following sentence: When wires are connected to the battery from the various electrical circuits within the minivan, the potential difference between the two terminals is a) equal to 12 V. b) less than 12 V. c) greater than 12 V. d) equal to zero V.
d) the amount of charge needed to produce a certain potential difference across a capacitor
What is capacitance? a) the amount of charge on a capacitor b) the amount of current flowing into or out of a capacitor c) the maximum amount of charge a capacitor can hold d) the amount of charge needed to produce a certain potential difference across a capacitor e) the amount of potential difference across a capacitor
c) C/V
The unit of capacitance is the farad (F). Which of the following combinations of units is equivalent to the farad? a) N/C b) V/C c) C/V d) J/C e) (N*m)/(C*s)
a) The equivalent capacitance is the sum of the three capacitances.
Three capacitors are connected in parallel to a battery. How is the equivalent capacitance for this circuit determined? a) The equivalent capacitance is the sum of the three capacitances. b) The equivalent capacitance is the sum of the three capacitances divided by three. In other words, the equivalent capacitance is the average capacitance in the circuit. c) The potential drop across each capacitor is measured and multiplied by each capacitance before adding them together. d) A resistor is used to replace one capacitor at a time. Then, the current through the resistor is measured and used to determine the charge on each capacitor. The sum of the charges is then divided by the emf of the battery to find the equivalent capacitance. e) Unlike resistors, an equivalent capacitance cannot be found by any simple means.
b) The equivalent capacitance is less than the sum of the individual capacitances.
Three capacitors are connected in series to a battery. Which one of the following statements concerning this situation is true? a) The amount of charge on each capacitor depends on its capacitance. If the capacitors have different capacitances, they will have differing amounts of charge on their plates. b) The equivalent capacitance is less than the sum of the individual capacitances. c) The battery must move more charge when the capacitors are connected in series than when connected in parallel. d) An equivalent capacitance can be found for capacitors connected in series, but not when they are connected in parallel. e) The equivalent capacitance is equal to the sum of the individual capacitances.
a) Given the directions of the magnetic field and the velocity of a charged particle, it is used to find the direction of the magnetic force on the particle.
What is Right-Hand Rule used to determine? a) Given the directions of the magnetic field and the velocity of a charged particle, it is used to find the direction of the magnetic force on the particle. b) Given the directions of the magnetic field and magnetic force on a charged particle, it is used to determine the magnitude and sign of charge on the particle. c) Given the magnitude and sign of the charge on a particle and the direction of the magnetic force, it is used to determine the net force on the particle. d) It is used to determine the direction of the "reaction force" when applying Newton's third law of motion to the particle.
d) The magnetic field at the center of the larger loop is one-half that at the center of the smaller loop.
Two circular loops carry identical currents, but the radius of one loop is twice that of the other. How do the magnetic fields at the centers of the loops compare? a) In both cases, the magnetic field at the center would be zero tesla. b) The magnetic field at the center of the larger loop is twice that at the center of the smaller loop. c) The magnetic field at the center of the larger loop is the same as that at the center of the smaller loop. d) The magnetic field at the center of the larger loop is one-half that at the center of the smaller loop. e) The magnetic field at the center of the larger loop is one-fourth that at the center of the smaller loop
b) 2i
Two identical resistors are connected in series across the terminals of a battery with a voltage V and a current i flows through the circuit. If one of the resistors is removed from the circuit and the remaining one connected across the terminals of the battery, how much current would flow through the circuit? a) 4i b) 2i c) i d) i/2 e) i/4
a) The magnetic field in the plane of the wires at the midpoint between the two wires is equal to zero tesla.
Two long wires are parallel to each other. One wire carries a current directed due east and the other carries a current of the same magnitude, but directed due west. Which one of the following statements concerning this situation is false? a) The magnetic field in the plane of the wires at the midpoint between the two wires is equal to zero tesla. b) The magnetic forces due to the currents carried by the wires causes the wires to move apart. c) If you are looking toward the west along the wire carrying the current toward the west, the magnetic field lines are directed clockwise around the wire. d) The magnetic field produced by each wire has its greatest magnitude outside, but near the surface of the wire.
c) a long coil of wire in the shape of a helix
What is a solenoid? a) a single loop of wire in the shape of a circle b) a radio antenna c) a long coil of wire in the shape of a helix d) a scanning mechanism inside of a television e) a magnet that is inserted into a coil of wire
a) When the two resistors are wired in parallel, the equivalent resistance is less than if they are wired in series.
Two resistors can be either connected to a battery in series or in parallel. In which case, if either, is the equivalent resistance the smallest? a) When the two resistors are wired in parallel, the equivalent resistance is less than if they are wired in series. b) When the two resistors are wired in series, the equivalent resistance is less than if they are wired in parallel. c) Both series and parallel wiring will result in the same equivalent resistance. d) It is not possible to know which method of wiring will result in the lowest equivalent resistance without knowing the values of the two resistances.
e) 9
Two solenoids, A and B, have the same length and cross-sectional area. Solenoid B has three times the number of turns per unit length. What is the ratio of the self-inductance of solenoid B to that of solenoid A? a) 1/3 b) √3 c) 3 d) 6 e) 9
d) the magnetic fields are cylindrically symmetric
Under which of the following conditions is Ampere's law most easily applied? a) the currents are all in the same direction b) the magnetic fields are spherically symmetrical c) no currents are present within the system d) the magnetic fields are cylindrically symmetric e) no charged particles are present in the system
d) Increasing the capacitance increases the charging time since the capacitor can hold more charge
What effect, if any, does increasing the capacitance in an RC circuit have on the charging of the capacitor? a) The capacitance has no effect on the charging of the capacitor, which is determined by the emf of the battery and the circuit resistance. b) Increasing the capacitance causes the charging time to increase since the rate at which charges are moving to the capacitor increases. c) The charging time will decrease as the capacitance is increased because the rate at which charges are moving to the capacitor decreases. d) Increasing the capacitance increases the charging time since the capacitor can hold more charge. e) Increasing the capacitance decreases the charging time since the emf of the battery will be reduced.
c) The charging time will increase as the resistance is increased because the rate at which charges are moving to the capacitor decreases.
What effect, if any, does increasing the resistance in an RC circuit have on the charging of the capacitor? a) The resistance has no effect on the charging of the capacitor, which is determined by the emf of the battery and the capacitance of the capacitor. b) Increasing the resistance causes the charging time to increase since the rate at which charges are moving to the capacitor increases. c) The charging time will increase as the resistance is increased because the rate at which charges are moving to the capacitor decreases. d) Increasing the resistance increases the charging time since the emf of the battery will be reduced. e) Increasing the resistance decreases the charging time since the emf of the battery will be reduced.
a) The capacitance of the capacitor increases.
What happens to a capacitor when an insulator is inserted between the two conductors of the capacitor? a) The capacitance of the capacitor increases. b) Electrons from the negative plate travel to the positive plate. c) The electric field inside the capacitor increases. d) There is no change to the capacitor. The insulator just keeps the two conductors separated. e) The insulator reduces the electric field between
d) A real emf device has an internal resistance, but an ideal emf device does not.
What is the primary difference between an ideal emf device and a real emf device? a) The electric potential of a real emf device is limited. b) The resistance of a real emf device is finite, but the resistance of an ideal emf device is assumed to be infinite. c) A real emf device can carry an electric current, but an ideal emf device does not. d) A real emf device has an internal resistance, but an ideal emf device does not. e) A real emf device has a potential difference across its terminals, but an ideal emf device does not.
b) to allow the trajectory of charged particles moving in a magnetic field to be observed and measured
What is the use of a bubble chamber? a) to accelerate charged particles before they move into a magnetic field b) to allow the trajectory of charged particles moving in a magnetic field to be observed and measured c) to make a magnetic field within a region of space uniform d) to increase the mass of charged particles so that their trajectories are more easily observed e) to charge a neutral particle or the increase the charge on a particle before it enters a magnetic field
a) It must be moving at an angle that is neither parallel to nor perpendicular to the magnetic field.
What must the initial state of motion of a charged particle be if it will follow a helical path in a magnetic field? a) It must be moving at an angle that is neither parallel to nor perpendicular to the magnetic field. b) It must be moving parallel to the magnetic field. c) It must be moving perpendicular to the magnetic field. d) It must be moving in the direction opposite to the magnetic field. e) It must be initially at rest when it is placed in the magnetic field.
d) 3.0 A
When a potential difference is applied to a certain copper wire, a current of 1.5 A passes through the wire. If the wire was removed from the circuit and replaced with a copper wire of twice the cross-sectional area, what current would flow through the new wire? Assume the wires are identical in all other aspects. a) 0.38 A b) 0.75 A c) 1.5 A d) 3.0 A e) 6.0 A
e) 6.0 A
When a potential difference is applied to a certain copper wire, a current of 1.5 A passes through the wire. If the wire was removed from the circuit and replaced with a copper wire of twice the diameter, what current would flow through the new wire? Assume the wires are identical in all other aspects. a) 0.38 A b) 0.75 A c) 1.5 A d) 3.0 A e) 6.0 A
d) when the potential difference across the plates of the capacitor is equal to the emf of the battery
When does a charging capacitor stop charging? a) when the amount of charge on the two plates is equal b) when the potential difference across the plates of the capacitor is equal to zero volts c) when the amount of charge on the two plates is infinitely large d) when the potential difference across the plates of the capacitor is equal to the emf of the battery e) when all of the charge available in the circuit has been forced to collect on the plates of the capacitor
a) upward
When lightning strikes, the current flows from the ground upward to the clouds above. What is the direction of the electric field of the lightning? a) upward b) downward c) perpendicular to the current at each location on the lightning bolt d) parallel to the ground
b) The new capacitance would be one-half of the previous value.
When the distance between charged parallel plates of a capacitor is d, the capacitance is C. If the distance is increased to 2d, how will the capacitance change, if at all? a) The new capacitance would be one-fourth of the previous value. b) The new capacitance would be one-half of the previous value. c) The new capacitance would be the same as the previous value. d) The new capacitance would be twice the previous value. e) The new capacitance would be four times the previous value.
c) The signs can be ignored; and at the end of the calculation inserted. The potential is negative if the charge distribution is negative.
When you calculate the potential at some point P due to a continuous charge distribution, the sign for the potential can be troublesome. If the charge distribution is negative, should the quantities dq and λ represent negative quanities? a) The sign on dq should be negative and the sign on λ should be positive. b) The sign on dq should be positive and the sign on λ should be negative. c) The signs can be ignored; and at the end of the calculation inserted. The potential is negative if the charge distribution is negative. d) The signs can be ignored; and at the end of the calculation inserted. The potential is positive if the charge distribution is negative. e) The signs can be ignored. The potential should have a positive sign, regardless of the sign of the charge distribution.
a) N/(A*m)
Which of the following combinations of units is equivalent to the tesla? a) N/(A*m) b) N*A/m c) (J*s)/(A*m) d) J/(C*s) e) C/(J*s)
a) ammeter
Which of the following devices is placed into a circuit to measure the current that passes through it? a) ammeter b) gaussmeter c) voltmeter d) diffractometer e) flowmeter
b) synchrotron
Which of the following instruments is used in the field of high energy physics to accelerate protons to very high energies along circular paths? a) magnetron b) synchrotron c) ignitron d) betatron e) quartertron
c) magnetic fields due to current carrying wires
Which of the following may be determined using Ampere's law? a) electric fields due to current carrying wires b) magnetic forces between two current carrying wires c) magnetic fields due to current carrying wires d) magnetic forces acting on charged particles e) magnetic fields due to permanent magnets
c) the time it takes a capacitor to reach 66% of its maximum charge
Which of the following quantities is equal to the time constant for a charging capacitor? a) the time it takes a capacitor to reach 33% of its maximum charge b) the time it takes a capacitor to reach 50% of its maximum charge c) the time it takes a capacitor to reach 66% of its maximum charge d) the time it takes a capacitor to reach 75% of its maximum charge e) the time it takes a capacitor to reach its maximum charge
c) The voltage across each resistor is necessarily the same.
Which of the following statements concerning resistors that are wired in parallel is true? a) The current through each resistor is necessarily the same. b) The equivalent resistance for the resistors in the circuit is the sum of the individual resistances. c) The voltage across each resistor is necessarily the same. d) The equivalent resistance for the resistors in the circuit is the product of the individual resistances. e) The equivalent resistance for the resistors in the circuit is the average of the individual resistances.
e) volt (V)
Which of the following units is/are the SI units for the electric potential? a) ampere (A) b) newton/coulomb (N/C) c) joule (J) d) gauss (G) e) volt (V)
b) Uniformly distribute charges over the surface of a conductor.
Which one of the following choices is not a possible way to produce a magnetic field? a) Set up a current in a long, straight wire. b) Uniformly distribute charges over the surface of a conductor. c) Make an object out of materials that have an intrinsic magnetic field. d) Pass a current through a coil of wire.
d) slide rule
Which one of the following choices is not one of Kirchoff's rules? a) junction rule b) emf rule c) loop rule d) slide rule e) resistance rule
b) farad
Which one of the following choices is the unit for capacitance? a) sievert b) farad c) apgar d) garnet e) plethron
c) The particle must not be under the influence of any other forces.
Which one of the following conditions is not a requirement for a particle to experience a magnetic force when placed in a magnetic field? a) The particle must be moving. b) The particle must be charged. c) The particle must not be under the influence of any other forces. d) The velocity of the particle must have a component that is perpendicular to the direction of the magnetic field.
a) the size and separation of the plates
Which one of the following is a primary consideration in determining the capacitance of a parallel-plate capacitor? a) the size and separation of the plates b) the potential difference across the plates c) the shape of the plates d) the particular materials used to fabricate the plates
b) tesla (T)
Which one of the following is the SI unit for the magnetic field? a) monopole (MP) b) tesla (T) c) fermi (Fm) d) gross (G) e) Oersted (oe)
b) radius of the wire
Which one of the following parameters is not used to determine the magnetic force on a current-carrying wire in a magnetic field? a) length of the wire b) radius of the wire c) direction of the magnetic field with respect to the direction of the current d) the strength of the magnetic field e) the magnitude of the electric current
d) the potential energy per unit charge
Which one of the following phrases best describes the electric potential of a charged particle? a) the total force exerted on or by the charged particle b) the force per unit charge c) the potential energy of the particle relative to infinity d) the potential energy per unit charge e) the potential energy per unit force on the particle
c) number density of charge carriers
Which one of the following quantities can be measured by performing a Hall effect measurement? a) magnetic monopole strength b) charge of the electron c) number density of charge carriers d) acceleration of an electron e) work function
b) Emf is the work done in moving a single charge from one terminal to the other of an emf device.
Which one of the following statements concerning emf is true? a) Emf is the work done in moving the current from one terminal to the other of an emf device. b) Emf is the work done in moving a single charge from one terminal to the other of an emf device. c) Emf is the force exerted on a single charge to move it from one terminal to the other of an emf device. d) Emf is the total charge moving from one terminal to the other of an emf device. e) Emf is the electromagnetic force that is exerted between the terminals of an emf device.
b) No work is done by the net electric force as a charge moves from one equipotential surface to another.
Which one of the following statements concerning equipotential surfaces is false? a) All points on an equipotential surface have the same electric potential. b) No work is done by the net electric force as a charge moves from one equipotential surface to another. c) The electric field created by one or more charges is everywhere perpendicular to the associated equipotential surfaces. d) The electric field created by one or more charges points in the direction of decreasing potential. e) There is a quantitative relationship between the electric field and the associated equipotential surfaces that surround one or more charges.
e) The net work done by electric forces that move a charge along an equipotential surface is equal to zero joules.
Which one of the following statements concerning equipotential surfaces is true? a) The electric field lines are directed parallel to the equipotential surface. b) Equipotential surfaces are a three dimensional representation of electric field lines. c) The electric potential at points on each equipotential surface is equal to that of all other equipotential surfaces. d) The net work done by electric forces that move a charge from one equipotential surface to another is equal to zero joules. e) The net work done by electric forces that move a charge along an equipotential surface is equal to zero joules.
d) The electric field is directed toward the right.
Which one of the following statements concerning the electric field inside a conductor is true if electrons are moving from right to left in a conducting wire? a) The electric field must be zero in this case. b) The electric field is directed perpendicular to the direction the electrons are moving. c) The electric field is directed toward the left. d) The electric field is directed toward the right.
e) An ideal voltmeter has almost no resistance.
Which one of the following statements is not a characteristic of a voltmeter? a) The voltmeter measures the voltage between two points in a circuit. b) The voltmeter is designed to measure nearly the same voltage that is present when the meter is not connected. c) The voltmeter is not placed directly into a circuit. d) The voltmeter is designed to draw very little current from the circuit being measured. e) An ideal voltmeter has almost no resistance.
a) The potential difference across each of the resistors is the same.
Which one of the following statements is true concerning resistors connected in parallel within an electric circuit? a) The potential difference across each of the resistors is the same. b) The current through each of the resistors is the same. c) The energy dissipated by each of the resistors is the same. d) The resistance of each of the resistors is the same. e) The resistivity of each of the resistors is the same.
b) The current through each of the resistors is the same.
Which one of the following statements is true concerning resistors connected in series within an electric circuit? a) The potential difference across each of the resistors is the same. b) The current through each of the resistors is the same. c) The energy dissipated by each of the resistors is the same. d) The resistance of each of the resistors is the same. e) The resistivity of each of the resistors is the same.
c) internal resistance
Which one of the following terms describes the resistance that a battery (or other emf device) has in a circuit? a) super resistance b) critical resistance c) internal resistance d) terminal resistance e) electroresistance
e) volts (V)
Which one of the following units is the correct SI unit for the electromotive force (emf)? a) newtons (N) b) coulombs (C) c) joules (J). d) amperes (A) e) volts (V)
c) The sum of the currents entering the junction must equal the sum of the currents exiting the junction.
While analyzing the currents within a circuit containing multiple components (such as batteries, resistors, etc.), which of the following statements concerning currents flowing into a single junction must be true? a) The sum of the currents entering the junction must equal the total current through the battery. b) The sum of the currents entering the junction must equal zero. c) The sum of the currents entering the junction must equal the sum of the currents exiting the junction. d) The currents entering the junction must follow only one of the possible exit paths. e) The currents entering the junction may exit back along the path from which they entered.
d) The electric field in wire A is twice that in wire B.
Wires A and B are identical, except that the length of wire A is one-half that of wire B. If the same potential difference is applied between the two ends of each wire, how does the electric field within wire A compare to that in wire B? a) The electric field in wire A is one fourth that in wire B. b) The electric field in wire A is one half that in wire B. c) The electric field in wire A is the same as that in wire B. d) The electric field in wire A is twice that in wire B. e) The electric field in wire A is four times that in wire B.
