PHY EXAM 2 MC

A circular coil lies flat on a horizontal table. A bar magnet is held above its center with its south pole pointing down. The stationary magnet induces (when viewed from above) (A) No current in the coil. (B) A clockwise current in the coil. (C) A counterclockwise current in the coil. (D) A current whose direction cannot be determined from the information given.

(A) No current in the coil.

3. A proton, moving west, enters a magnetic field of a certain strength. Because of this field the protons curves upward. What is the direction of the magnetic field? (A) South. (B) North. (C) East. (D) West. (E) Downward.

(A) South.

A horizontal rod (oriented in the east-west direction) is moved northward at constant velocity through a magnetic field that points straight down. Make a statement concerning the potential induced across the rod. (A) The west end of the rod is at higher potential than the east end. (B) The east end of the rod is at higher potential than the west end. (C) The top surface of the rod is at higher potential than the bottom surface. (D) The bottom surface of the rod is at higher potential than the top surface. (E) All points of the rod are at the same potential.

(A) The west end of the rod is at higher potential than the east end.

1. If the strength of the magnetic field applied to a loop of wire is doubled, what happens to the magnetic flux through that loop assuming that all the other parameters remain unchanged? (A) It stays the same. (B) It is doubled. (C) It is tripled. (D) It is quadrupled. (E) It is reduced by a factor of 2.

(B) It is doubled.

A current in a solenoid coil creates a magnetic field inside that coil. The field strength is directly proportional to: (A) The coil area. (B)The current. (C) Both a and b are valid choices. (D) None of the above choices is valid.

(B)The current.

A horizontal wire carries a current straight away from you. From your point of view, the magnetic field caused by this current (A) Points directly away from you. (B) Points to the left. (C) Circles the wire in a clockwise direction. (D) Circles the wire in a counter-clockwise direction. (E) Points to the right perpendicular to the wire.

(C) Circles the wire in a clockwise direction.

A proton in a magnetic field does not experience a force. Which of the following statements is correct with respect to the situation? I. The proton may have a velocity of zero m/s. II. The proton may be moving parallel to the direction of the magnetic field. (A) Statement I only. (B) Statement II only. (C) Neither statement I nor statement II. (D) Both statement I and statement II.

(D) Both statement I and statement II.

If the number of turns in the rectangular coil of wire that is rotating in a magnetic field is doubled, what happens to the induced emf, assuming all the other variables remain the same? (A) It stays the same. (B) It is reduced by a factor of 4. (C) It is reduced by a factor of 2. (D) It is doubled. (E) It is quadrupled.

(D) It is doubled.

Electric field lines near a positive point charge (A) circle clockwise. (B) circle counter-clockwise. (C) radiate inward. (D) radiate outward. (E) do not exist.

(D) radiate outward.

Two long, parallel wires carry currents of different magnitudes. If the current in each wire is doubled, what happens to the magnitude of the force between these two wires? (A) It is doubled. (B) It is tripled. (C) It is reduced by a factor of 2. (D) It stays the same. (E) It is quadrupled.

(E) It is quadrupled.

A horizontal rod (oriented in the north-south direction) is moved westward at constant velocity through a magnetic field that points straight up. Make a statement concerning the potential induced across the rod. A) The north end of the rod is at higher potential than the south end. B) The south end of the rod is at higher potential than the north end. C) Both ends of the rod are at the same non-zero potential. D) Both ends of the rod are at zero potential.

A) The north end of the rod is at higher potential than the south end.

An electron has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. The direction of the magnetic field is A) To the west. B) To the east. C) Upward. D) Downward.

A) To the west.

The force on a current-carrying wire in a magnetic field is equal to zero when A) the current is parallel to the field lines. B) the current is at a 30e angle with respect to the field lines. C) the current is at a 60e angle with respect to the field lines. D) the current is perpendicular to the field lines.

A) the current is parallel to the field lines.

An electron, moving west, enters a magnetic field. Because of this field the electron curves upward. We may conclude that the magnetic field must have a component A) towards the north. B) towards the south. C) upward. D) downward. E) towards the west.

A) towards the north.

A proton, moving east, enters a magnetic field. Because of this magnetic field the proton curves downward. We may conclude that the magnetic field must have a component A) towards the south. B) towards the north. C) towards the west. D) upward. E) downward.

A) towards the south.

A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. A uniform electric field is also present. Due to the combined effect of both fields, the particle does not change its velocity. What is the direction of the electric field? A) along the -y-axis B) along the +y-axis C) along the -x-axis D) along the +x-axis E) along the -z-axis

B) along the +y-axis

An electron moving along the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, then the magnetic field must have a component A) along the +z-axis B) along the -z-axis C) along the -x-axis D) along the +y-axis E) along the -y-axis

B) along the -z-axis

A straight bar magnet is initially 4 cm long, with the north pole on the right and the south pole on the left. If you cut the magnet in half, the right half will A) contain only a north pole B) contain a north pole on the right and a south pole on the left. C) contain only a south pole. D) no longer contain any poles.

B) contain a north pole on the right and a south pole on

The magnetic field produced by a long straight current-carrying wire is A) proportional to both the current in the wire and the distance from the wire B) proportional to the current in the wire and inversely proportional to the distance from the wire. C) inversely proportional to the current in the wire and proportional to the distance from the wire. D) inversely proportional to both the current in the wire and the distance from the wire.

B) proportional to the current in the wire and inversely proportional to the distance from the wire.

What is the direction of the magnetic force it produces on an electron that is moving perpendicularly toward the wire, also in the plane of the page, from your right? A) perpendicular to the page and towards you B) toward the bottom of the page C) toward the top of the page D) zero E) perpendicular to the page and away from yo

B) toward the bottom of the page

A circular loop of wire is rotated at constant angular speed about an axis whose direction can be varied. In a region where a uniform magnetic field points straight down, what must be the orientation of the loop's axis of rotation if the induced emf is to be zero? A) Any horizontal orientation will do. B) It must make an angle of 45e to the vertical. C) It must be vertical. D) none of the given answers

C) It must be vertical.

A current carrying circular loop of wire lies flat on a table top. When viewed from above, the current moves around the loop in a counterclockwise sense. What is the direction of the magnetic field caused by this current, inside the loop? The magnetic field A) Circles the loop in a clockwise direction. B) Circles the loop in a counterclockwise direction. C) Points straight up. D) Points straight down.

C) Points straight up.

Which one of the following statements is correct? A) Earth's geographic north pole is the north pole of Earth's magnetic field. B) Earth's geographic south pole is the south pole of Earth's magnetic field. C) The north pole of a magnet points towards Earth's geographic north pole. D) The north pole of a magnet points towards Earth's geographic south pole. E) None of the above statements is correct

C) The north pole of a magnet points towards Earth's geographic north pole. (but really canada from teachers notes)

A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. Because of an electric field along the +y- axis, the charge particle does not change velocity. What is the sign of this particle? A) positive B) negative C) The particle could be either positive or negative. D) None of the above choices is correct.

C) The particle could be either positive or negative.

A charged particle that is moving in a static uniform magnetic field A) will always experience a magnetic force, regardless of its direction of motion. B) may experience a magnetic force which will cause its speed to change. C) may experience a magnetic force, but its speed will not change. D) may experience a magnetic force, but its direction of motion will not change. E) None of the above statements are true.

C) may experience a magnetic force, but its speed will not change.

Faraday's law of induction states that the emf induced in a loop of wire is proportional to A) the magnetic flux. B) the magnetic flux density times the loop's area. C) the time variation of the magnetic flux. D) current divided by time.

C) the time variation of the magnetic flux.

A proton, moving north, enters a magnetic field. Because of this field, the proton curves downward. We may conclude that the magnetic field must have a component A) downward. B) upward. C) towards the east. D) towards the west. E) towards the north.

C) towards the east.

A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component A) towards the west. B) towards the east. C) towards the south. D) towards the north. E) downward.

C) towards the south.

A circular coil lies flat on a horizontal table. A bar magnet is held above its center with its north pole pointing down, and released. As it approaches the coil, the falling magnet induces (when viewed from above) a. No current in the coil. b. A clockwise current in the coil. c. A counterclockwise current in the coil. d. A current whose direction cannot be determined from the information provided

C. Counterclockwise

At a particular instant, an electron moves toward the east in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is A. Zero B. upward C. Toward the North D. Toward the south E. Downward

C. Toward the North

If you were to cut a small permanent bar magnet in half, A) one piece would be a magnetic north pole and the other piece would be a south pole. B) neither piece would be magnetic. C) each piece would in itself be a smaller bar magnet with both north and south poles. D) None of these statements is true.

C. each piece would in itself be a smaller bar magnet with both north and south poles

A long straight wire lies on a horizontal table and carries an ever-increasing current northward. Two coils of wire lie flat on the table, one on either side of the wire. When viewed from above, the induced current circles A) Clockwise in both coils. B) Counterclockwise in both coils. C) Clockwise in the east coil and counterclockwise in the west coil. D) Counterclockwise in the east coil and clockwise in the west coil.

D) Counterclockwise in the east coil and clockwise in the west coil.

Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at the point exactly between the two wires A) Points up. B) Points down. C) Points toward you. D) Is zero.

D) Is zero.

An electron moving in the +y direction, at right angles to a magnetic field, experiences a magnetic force in the -x direction. The direction of the magnetic field is in the A) -x direction. B) +x direction. C) +y direction. D) -z direction. E) +z direction.

E) +z direction.

Lenz's Law is a consequence of the law of conservation of A) momentum. B) charge. C) mass. D) electric field. E) energy.

E) energy.

A positive charge is moving to the right and experiences an upward magnetic force, as shown in the figure. In which direction must the magnetic field have a component? A) to the right B) to the left C) upward D) out of the page E) into the page

E) into the page

8. An electric generator transforms A) alternating current into direct current. B) direct current into alternating current. C) electrical energy into mechanical energy. D) chemical energy into electrical energy. E) mechanical energy into electrical energy.

E) mechanical energy into electrical energy.

A proton is to orbit Earth at the equator using Earth's magnetic field to supply part of the necessary centripetal force. In what direction should the proton move? A) upward B) northward C) southward D) eastward E) westward

E) westward

A horizontal rod (oriented in the east-west direction) is moved northward at constant velocity through a magnetic field that points straight down. Make a statement concerning the potential induced across the rod. a. The west end of the rod is at higher potential than the east end. b. The east end of the rod is at higher potential than the west end. c. The top surface of the rod is at higher potential than the bottom surface. d. The bottom surface of the rod is at higher potential than the top surface.

The west end of the rod is at higher potential than the east end

As the frequency of the AC voltage across an inductor approaches zero, the inductive reactance of that coil a. Approaches zero. b. Approaches infinity. c. Approaches unity. d. None of the given answers

a. Approaches zero.

A bar magnet is falling through a loop with constant velocity. The north pole enters first. As the south pole leaves the loop of wire, the induced current (as viewed from above) will be: a. Clockwise. b. Counterclockwise. c. Zero. d. Along the length of the magnet.

a. Clockwise.

A long straight wire carries current toward the east. A proton moves toward the east alongside and just south of the wire. What is the direction of the force on the proton? a. North. b. South. c. Up. d. Down

a. North.

The path of a charged particle moving parallel to a uniform magnetic field will be: a. Straight line. b. Circle. c. Ellipse. d. Parabola.

a. Straight line.

A coil lies flat on a table top in a region where the magnetic field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the direction of the induced current in this coil as the field fades? a. The induced current flows counterclockwise. b. The induced current flows clockwise. c. There is no induced current in this coil. d. The current flows clockwise initially, and then it flows counterclockwise before stopping.

a. The induced current flows counterclockwise.

A charged particle is observed traveling in a circular path in a uniform magnetic field. If the particle had been traveling twice as fast, the radius of the circular path would be a. Twice the original radius. b. Four times the original radius. c. One-half the original radius. d. One-fourth the original radius.

a. Twice the original radius.

55. If the number of turns on the secondary coil of a transformer are less than those on the primary, the result is a a. step-down transformer b. step-up transformer c. a 120-V transformer d. a dc transformer

a. step-down transformer

A coil lies flat on a table top in a region where the magnetic field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the sense of the induced current in this coil as the field fades? a. The induced current flows counterclockwise. b. The induced current flows clockwise. c. There is no induced current in this coil. d. The current flows clockwise initially, and then it flows counterclockwise before stopping.

a.The induced current flows counterclockwise.

A charged particle moves across a constant magnetic field. The magnetic force on this particle a. Changes the particle's speed. b. Causes the particle to accelerate. c. Is in the direction of the particle's motion. d. Changes the particle's speed causing the particle to accelerate.

b. Causes the particle to accelerate.

A current in a solenoid coil creates a magnetic field inside that coil. The field strength is directly proportional to: a. The coil area. b. The current. c. Both a and b are valid choices. d. None of the above choices are valid.

b. The current.

An electron has an initial velocity to the north but is observed to curve upward as the result of a magnetic field. The direction of the magnetic field is a. To the west. b. To the east. c. Upward. d. Downward.

b. To the east.

At double the distance from a long current-carrying wire, the strength of the magnetic field produced by that wire decreases to a. 1/8 of its original value. b. 1/4 of its original value. c. 1/2 of its original value. d. None of the given answers.

c. 1/2 of its original value.

A bar magnet falls through a loop of wire with the north pole entering first. As the north pole enters the wire, the induced current will be (as viewed from above) a. Zero. b. Clockwise. c. Counterclockwise. d. To top of loop.

c. Counterclockwise.

At a particular instant, a proton moves eastward at speed V in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is a. Zero. b. Directed upward. c. Directed to the north. d. Directed to the south.

c. Directed to the north.

At a particular instant, a proton moves eastward at speed V in a uniform magnetic field that is directed straight downward. The magnetic force that acts on it is a. Zero. b. Directed upward. c. Directed to the north. d. Directed to the south.

c. Directed to the north.

How is the energy stored in a current carrying inductor related to its self-inductance, L? a. Directly proportional to L2. b. Directly proportional to L1/2. c. Directly proportional to L. d. Inversely proportional to L.

c. Directly proportional to L.

A proton, moving north, enters a magnetic field of a certain strength. Because of this field the protons curves downward. What is the direction of the magnetic field? a. Down ward. b. Upward. c. East. d. West.

c. East.

A vertical wire carries a current straight up in a region where the magnetic field vector points due south. What is the direction of the resulting force on this current? a. Down. b. North. c. East. d. West.

c. East.

A particle carrying a charge of +e travels in a circular path in a uniform magnetic field. If instead the particle carried a charge of +2e, the radius of the circular path would have been a. Twice the original radius. b. Four times the original radius. c. One-half the original radius. d. One-fourth the original radius.

c. One-half the original radius.

The direction of the force on a current-carrying wire in a magnetic field is described by which of the following? a. Perpendicular to the current only. b. Perpendicular to the magnetic field only. c. Perpendicular to both the current and the magnetic field. d. Perpendicular to neither the current or the magnetic field.

c. Perpendicular to both the current and the magnetic field.

Two long parallel wires are placed side-by-side on a horizontal table. If the wires carry current in the same direction, a. One wire is lifted slightly as the other wire is forced against the table's surface. b. Both wires are lifted slightly. c. The wires attract each other. d. The wires repel each other.

c. The wires attract each other.

A rectangular coil lies flat on a horizontal table. A bar magnet is held above the center of the coil with its south pole pointing down. What is the direction of the induced current in the coil (looking from above)? a. Clockwise. b. Counterclockwise. c. There is no current in the coil. d. Away from the north pole and toward the south pole.

c. There is no current in the coil.

Which of the following is correct? a. When a current carrying wire is in your right hand, thumb in the direction of the magnetic field lines, your fingers point in the direction of the current. b. When a current carrying wire is in your left hand, thumb in the direction of the magnetic field lines, your fingers point in the direction of the current. c. When a current carrying wire is in your right hand, thumb in the direction of the current, your fingers point in the direction of the magnetic field lines. d. When a current carrying wire is in your left hand, thumb in the direction of the current, your fingers point in the direction of the magnetic field lines.

c. When a current carrying wire is in your right hand, thumb in the direction of the current, your fingers point in the direction of the magnetic field lines.

Two long, parallel wires carry currents of different magnitudes. If the current in one of them is doubled and the current in the other one is halved, what happens to the magnitude of the force between these two wires? a. It is doubled. b. It is tripled. c. It is reduced by a factor of 2. d. It stays the same.

d. It stays the same.

5. A current carrying loop of wire lies flat on a table top. When viewed from above, the current moves around the loop in a counterclockwise sense. What is the direction of the magnetic field caused by this current, outside the loop? The magnetic field a. Circles the loop in a clockwise direction. b. Circles the loop in a counterclockwise direction. c. Points straight up. d. Points straight down

d. Points straight down.

The magnetic forces that two parallel wires with unequal currents flowing in the opposite directions exert on each other are A. Attractive and unequal in magnitude. b. Repulsive and unequal in magnitude. c. Attractive and equal in magnitude. d. Repulsive and equal in magnitude.

d. Repulsive and equal in magnitude.

The force on a current-carrying wire in a magnetic field is the strongest when a. The current is parallel to the field lines. b. The current is at a 30° angle with respect to the field lines. c. The current is at a 60° angle with respect to the field lines. d. The current is perpendicular to the field lines.

d. The current is perpendicular to the field lines.

If you look directly down on the north pole of a bar magnet, the magnetic field points a. To the right. b. To the left. c. Away from you. d. Toward you.

d. Toward you.

A vertical wire carries a current straight up in a region where the magnetic field vector points due north. What is the direction of the resulting force on this current? a. Down. b. North. c. East. d. West.

d. West.

A vertical wire carries a current straight up in a region where the magnetic field vector points due north. What is the direction of the resulting force on this current? a. Down. b. North. (4) c. East. d. West.

d. West.

Resonance in a series RLC circuit occurs when a. XL is greater than XC. b. XC is greater than XL. c. (XL - XC)2 is equal to R2. d. XC equals XL.

d. XC equals XL.

At double the distance from a long current carrying wire, the strength of the magnetic field produced by that wire decrease to A.) 1/8 of its orginal value B.) ¼ of its original value C.) ½ of its original value D.) None of the given answers

C.) ½ of its original value

1 T is equivalent to A) 1 Nm/A. B) 1 NA/m. C) Vm/A. D) N/Am.

D) N/Am.

We observe that a moving charged particle experiences no magnetic force. From this we can definitely conclude that A) no magnetic field exists in that region of space. B) the particle must be moving parallel to the magnetic field. C) the particle is moving at right angles to the magnetic field. D) either no magnetic field exists or the particle is moving parallel to the field. E) either no magnetic field exists or the particle is moving perpendicular to the field.

D) either no magnetic field exists or the particle is moving parallel to the field.

1. A charged particle moves with a constant speed through a region where a uniform magnetic field is present. If the magnetic field points straight upward, the magnetic force acting on this particle will be maximum when the particle moves A) upward at an angle of 45° above the horizontal. B) straight downward. C) straight upward. D) horizontally

D) horizontally

An electron, moving south, enters a magnetic field. Because of this field, the electron curves upward. We may conclude that the magnetic field must have a component A) downward. B) towards the east. C) upward. D) towards the west. E) towards the north.

D) towards the west.

A vertical wire carries a current straight up in a region where the magnetic field vector points due north. What is the direction of the resulting force on this current? A.) Down B.) North C.) East D.) West

D.) West

A horizontal wire carries a current straight toward you. From your point of view, the magnetic field caused by this current a. Points directly away from you. b. Points to the left. c. Circles the wire in a clockwise direction. d. Circles the wire in a counter-clockwise direction.

d. Circles the wire in a counter-clockwise direction.

If the number of turns in a rectangular coil of wire that is rotating in a magnetic field is doubled, what happens to the induced emf, assuming all the other variables remain the same? a. It stays the same. b. It is reduced by a factor of 2. c. It is reduced by a factor of 4. d. It is doubled.

d. It is doubled.