PHY 2185: iClicker Exam 3 Review (Chapters 10-12)

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

a) +ε

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.

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 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.

a) It must be moving at an angle that is neither parallel to nor perpendicular to the magnetic field.

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) N/(A*m)

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.

a) The magnetic field in the plane of the wires at the midpoint between the two wires is equal to zero tesla.

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.

a) The potential difference across each of the resistors is the same.

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.

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.

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.

a) The two wires will attract each other, even if no external magnetic field is applied to the wires.

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.

a) When the two resistors are wired in parallel, the equivalent resistance is less than if they are wired in series.

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

a) ammeter

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.

a) equals the sum of the magnitudes of the currents directed out of the junction.

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.

a) remain at rest.

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

a) west

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°

b) 0° and 180°

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

b) 2i

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.

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.

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) Emf is the work done in moving a single charge from one terminal to the other of an emf device.

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.

b) It will follow a circular path in the plane perpendicular to the magnetic field lines.

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.

b) The current through each of the resistors is the same.

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.

b) The magnetic field after the stretching is one-half the value it was before stretching.

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.

b) The two wires will repel each other, even if no external magnetic field is applied to the wires.

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.

b) Uniformly distribute charges over the surface of a conductor

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

b) electrons

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.

b) less than 12 V.

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

b) radius of the wire

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

b) synchrotron

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) tesla (T)

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

b) to allow the trajectory of charged particles moving in a magnetic field to be observed and measured

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°

c) 90°

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.

c) It will follow a straight line path in the same direction as it was initially traveling.

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.

c) The charging time will increase as the resistance is increased because the rate at which charges are moving to the capacitor decreases.

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.

c) The particle must not be under the influence of any other forces.

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.

c) The sum of the currents entering the junction must equal the sum of the currents exiting the junction.

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.

c) The voltage across each resistor is necessarily the same.

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

c) a long coil of wire in the shape of a helix

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.

c) equals the sum of the potential rises.

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) in the direction that is perpendicular to both the magnetic field and the velocity

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

c) internal resistance

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) magnetic fields due to current carrying wires

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

c) number density of charge carriers

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 time it takes a capacitor to reach 66% of its maximum charge

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

d) -iR

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

d) 2, 3, and 4 only

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.

d) A real emf device has an internal resistance, but an ideal emf device does not.

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.

d) Increasing the capacitance increases the charging time since the capacitor can hold more charge

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.

d) The magnetic field at the center of the larger loop is one-half that at the center of the smaller loop.

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.

d) The magnetic field is parallel to the direction of the current in the wire.

Which of the following scientists is credited with the discovery of the electron? a) Planck b) Curie c) Maxwell d) Thompson e) Fermi

d) Thompson

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

d) slide rule

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) the magnetic fields are cylindrically symmetric

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

d) when the potential difference across the plates of the capacitor is equal to the emf of the battery

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

e) 1 and 3 only

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°

e) 180°

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

e) 3R

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.

e) An ideal voltmeter has almost no resistance.

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

e) in the direction that is perpendicular to both the wire and to the radial direction

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

e) vertically downward

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)

e) volts (V)