Question 1

Magnetic fields affect

Accepted Answer

A)  neither electric charges in motion nor electric charges at rest. 
B)  both electric charges in motion and electric charges at rest. 
C)  only electric charges in motion. 
D)  only electric charges at rest. 
A)  neither electric charges in motion nor electric charges at rest. 
B)  both electric charges in motion and electric charges at rest. 
C)  only electric charges in motion. 
D)  only electric charges at rest.

Question 2

Two current-carrying wires are parallel to one another and separated by 1 cm. If the distance between them is increased to 2 cm the new force will be what factor times the original force?

Accepted Answer

A)  ¼ 
B)  ½ 
C)  1 
D)  2 
E)  4 
A)  ¼ 
B)  ½ 
C)  1 
D)  2 
E)  4

Question 3

When a switch is closed allowing current to flow in coil A, the current induced in a nearby coaxial but unconnected coil B will flow

Accepted Answer

A)  only momentarily and then stop 
B)  steadily until the current flow in A is shutoff 
C)  will not flow at all since the coils are not connected 
D)  will keep flowing long after the current in A is shut off 
A)  only momentarily and then stop 
B)  steadily until the current flow in A is shutoff 
C)  will not flow at all since the coils are not connected 
D)  will keep flowing long after the current in A is shut off

Question 4

In outer space, you observe a straight stream of electrons flowing past you at 14.5 miles per second, about the same speed that Mars moves on its orbit around the sun.   You maneuver your spacecraft to face the current so that the electrons are moving from left to right and so that you are 10 m from the stream. Now you fire your rockets and boost your speed so that you are also moving at 14.5 miles per second, exactly at the same speed and direction as the electrons. In what direction does a compass needle point now?

Accepted Answer

A)  up   
B)  down   
C)  left   
D)  right   
E)  You observe no magnetic field. 
A)  up   
B)  down   
C)  left   
D)  right   
E)  You observe no magnetic field.

Question 5

The sketch below shows a bar magnet in a loop of wire with the bar perpendicular to the plane of the loop. The left-hand side shows the magnet being spun around its long axis while on the right side the magnet is turned end-over-end. Which case creates a larger induced current in the loop?

Accepted Answer

A)  The right-hand side. 
B)  The left-hand side. 
C)  Neither situation produces an induced current. 
D)  The induced current is the same in each case and is not zero. 
A)  The right-hand side. 
B)  The left-hand side. 
C)  Neither situation produces an induced current. 
D)  The induced current is the same in each case and is not zero.

Question 6

What would happen if you had a car made completely of plastic, with no metal parts, and you drove over a vehicle sensor embedded in the road surface?

Accepted Answer

A)  You would overload the sensor, so this is an excellent method for forcing all lights to turn green. 
B)  The circuit would detect the absence of magnetic flux, thereby working normally. 
C)  The sensor would signal with the opposite polarity, indicating you've already gone through the intersection. 
D)  The sensor would not notice you or your vehicle, and you'd be stuck at the red light. 
A)  You would overload the sensor, so this is an excellent method for forcing all lights to turn green. 
B)  The circuit would detect the absence of magnetic flux, thereby working normally. 
C)  The sensor would signal with the opposite polarity, indicating you've already gone through the intersection. 
D)  The sensor would not notice you or your vehicle, and you'd be stuck at the red light.

Question 7

Which of these will always produce a magnetic field?

Accepted Answer

A)  A positive charge at rest 
B)  Another magnetic field 
C)  A moving charge 
D)  A negative charge at rest 
A)  A positive charge at rest 
B)  Another magnetic field 
C)  A moving charge 
D)  A negative charge at rest

Question 8

A permanent magnet is produced when

Accepted Answer

A)  magnetic fields of large groups of individual atoms are permanently aligned. 
B)  electrons become stuck and cease to move. 
C)  electrical fields exchange electrons with the magnetic fields. 
D)  current is made to circulate in a clockwise direction in a loop of wire. 
A)  magnetic fields of large groups of individual atoms are permanently aligned. 
B)  electrons become stuck and cease to move. 
C)  electrical fields exchange electrons with the magnetic fields. 
D)  current is made to circulate in a clockwise direction in a loop of wire.

Question 9

A transformer is to be used to step down voltage from an alternating current source from 220 V to 110 V. If the primary has 120 turns, then the number of turns in the secondary is

Accepted Answer

A)  2. 
B)  60. 
C)  240. 
D)  720. 
E)  1320. 
A)  2. 
B)  60. 
C)  240. 
D)  720. 
E)  1320.

Question 10

The unit used in expressing magnetic field strength is the __________.

Accepted Answer

The answer of The unit used in expressing magnetic field...

Question 11

Two parallel wires each carrying a current in opposite directions will __________________ one another.

Accepted Answer

The answer of Two parallel wires each carrying a current...

Question 12

You could use two parallel wires to move objects 1 and 2 apart if each wire is embedded in its own object and if

Accepted Answer

A)  the currents in the wires are in opposite directions. 
B)  the currents in the wires are in the same direction. 
C)  one wire carries a current and the other wire has zero current. 
A)  the currents in the wires are in opposite directions. 
B)  the currents in the wires are in the same direction. 
C)  one wire carries a current and the other wire has zero current.

Question 13

Think of a closed rectangular loop of wire around the edge of this page. A magnetic field perpendicular to the page points upward and increases in strength in a certain time. During this time the conventional current induced in the loop will be

Accepted Answer

A)  clockwise. 
B)  counterclockwise. 
C)  zero. 
D)  continually changing direction. 
A)  clockwise. 
B)  counterclockwise. 
C)  zero. 
D)  continually changing direction.

Question 14

A bar magnet is broken in half and the magnetic field around one piece is mapped out. What is wrong with this picture?

Accepted Answer

A)  The field lines are pointing in the wrong direction. 
B)  The field lines should converge on the "N." 
C)  There is no south pole. 
D)  Nothing; this is how the field looks around a broken magnet. 
A)  The field lines are pointing in the wrong direction. 
B)  The field lines should converge on the "N." 
C)  There is no south pole. 
D)  Nothing; this is how the field looks around a broken magnet.

Question 15

A current flowing through a long, straight wire causes a magnetic field that points

Accepted Answer

A)  along the wire. 
B)  along concentric circles around the wire. 
C)  radially inward toward the wire. 
D)  radially outward from the wire. 
A)  along the wire. 
B)  along concentric circles around the wire. 
C)  radially inward toward the wire. 
D)  radially outward from the wire.

Question 16

A solenoid carrying an electric current, if free to rotate when placed in a magnetic field, will tend to orient its axis _________________________________ (parallel, perpendicular, anti-parallel) to the magnetic field.

Accepted Answer

The answer of A solenoid carrying an electric current, if...

Question 17

A battery is causing a large current in a solenoid (helical coil of wire). A bar magnet is held at rest nearby, aligned with the axis of the solenoid, with its south pole closest to the solenoid. The bar magnet is being repelled by the solenoid. Which of the following statements is true of the conventional current in the solenoid?

Accepted Answer

A)  The current in the solenoid increases. 
B)  The current in the solenoid decreases. 
C)  The current in the solenoid is flowing counterclockwise as seen from the bar magnet. 
D)  The current in the solenoid is flowing clockwise as seen from the bar magnet. 
E)  The direction of the current in the solenoid alternates with a constant frequency. 
A)  The current in the solenoid increases. 
B)  The current in the solenoid decreases. 
C)  The current in the solenoid is flowing counterclockwise as seen from the bar magnet. 
D)  The current in the solenoid is flowing clockwise as seen from the bar magnet. 
E)  The direction of the current in the solenoid alternates with a constant frequency.

Question 18

If an electron is placed at rest near a bar magnet, the electron will

Accepted Answer

A)  accelerate away from the negative pole of the magnet. 
B)  not move at all. 
C)  be attracted to the positive pole of the magnet. 
D)  move in a circular path around the north pole of the magnet. 
A)  accelerate away from the negative pole of the magnet. 
B)  not move at all. 
C)  be attracted to the positive pole of the magnet. 
D)  move in a circular path around the north pole of the magnet.

Question 19

Faraday's Law states that a voltage is induced in a circuit when there is a changing ___________________ passing through the circuit.

Accepted Answer

magnetic f

Question 20

The south pole of a bar magnet is moved toward a short helical coil of wire (solenoid) along the axis of the coil. The coil has 100 turns and the ends of the coil are connected to form a closed circuit. If the coil is replaced with a single loop of the same type of wire, and the magnet is moved exactly as before, the magnet experiences a force that is

Accepted Answer

A)  the same as before. 
B)  attractive and 100 times larger. 
C)  attractive and 100 times smaller. 
D)  repulsive and 100 times larger. 
E)  repulsive and 100 times smaller. 
A)  the same as before. 
B)  attractive and 100 times larger. 
C)  attractive and 100 times smaller. 
D)  repulsive and 100 times larger. 
E)  repulsive and 100 times smaller.

Magnetic fields affect

Two current-carrying wires are parallel to one another and separated by 1 cm. If the distance between them is increased to 2 cm the new force will be what factor times the original force?

When a switch is closed allowing current to flow in coil A, the current induced in a nearby coaxial but unconnected coil B will flow

The sketch below shows a bar magnet in a loop of wire with the bar perpendicular to the plane of the loop. The left-hand side shows the magnet being spun around its long axis while on the right side the magnet is turned end-over-end. Which case creates a larger induced current in the loop?

What would happen if you had a car made completely of plastic, with no metal parts, and you drove over a vehicle sensor embedded in the road surface?

Which of these will always produce a magnetic field?

A permanent magnet is produced when

A transformer is to be used to step down voltage from an alternating current source from 220 V to 110 V. If the primary has 120 turns, then the number of turns in the secondary is

The unit used in expressing magnetic field strength is the __________.

Two parallel wires each carrying a current in opposite directions will __________________ one another.

You could use two parallel wires to move objects 1 and 2 apart if each wire is embedded in its own object and if

Think of a closed rectangular loop of wire around the edge of this page. A magnetic field perpendicular to the page points upward and increases in strength in a certain time. During this time the conventional current induced in the loop will be

A bar magnet is broken in half and the magnetic field around one piece is mapped out. What is wrong with this picture?

A current flowing through a long, straight wire causes a magnetic field that points

A solenoid carrying an electric current, if free to rotate when placed in a magnetic field, will tend to orient its axis _________________________________ (parallel, perpendicular, anti-parallel) to the magnetic field.

If an electron is placed at rest near a bar magnet, the electron will

Faraday's Law states that a voltage is induced in a circuit when there is a changing ___________________ passing through the circuit.

Physics, the Fundamental Science

Describing Motion

Falling Objects and Projectile Motion

Newtons Laws: Explaining Motion

Circular Motion, the Planets, and Gravity

Energy and Oscillations

Momentum and Impulse

Rotational Motion of Solid Objects

The Behavior of Fluids

Temperature and Heat

Heat Engines and the Second Law of Thermodynamics

Electrostatic Phenomena

Electric Circuits

Making Waves

Light Waves and Color

Light and Image Formation

The Structure of the Atom

The Nucleus and Nuclear Energy

Relativity

Beyond Everyday Phenomena

Filters

Exam 14: Magnets and Electromagnetism

Magnetic fields affect

Two current-carrying wires are parallel to one another and separated by 1 cm. If the distance between them is increased to 2 cm the new force will be what factor times the original force?

When a switch is closed allowing current to flow in coil A, the current induced in a nearby coaxial but unconnected coil B will flow

The sketch below shows a bar magnet in a loop of wire with the bar perpendicular to the plane of the loop. The left-hand side shows the magnet being spun around its long axis while on the right side the magnet is turned end-over-end. Which case creates a larger induced current in the loop?

What would happen if you had a car made completely of plastic, with no metal parts, and you drove over a vehicle sensor embedded in the road surface?

Which of these will always produce a magnetic field?

A permanent magnet is produced when

A transformer is to be used to step down voltage from an alternating current source from 220 V to 110 V. If the primary has 120 turns, then the number of turns in the secondary is

The unit used in expressing magnetic field strength is the __________.

Two parallel wires each carrying a current in opposite directions will __________________ one another.

You could use two parallel wires to move objects 1 and 2 apart if each wire is embedded in its own object and if

Think of a closed rectangular loop of wire around the edge of this page. A magnetic field perpendicular to the page points upward and increases in strength in a certain time. During this time the conventional current induced in the loop will be

A bar magnet is broken in half and the magnetic field around one piece is mapped out. What is wrong with this picture?

A current flowing through a long, straight wire causes a magnetic field that points

A solenoid carrying an electric current, if free to rotate when placed in a magnetic field, will tend to orient its axis _________________________________ (parallel, perpendicular, anti-parallel) to the magnetic field.

If an electron is placed at rest near a bar magnet, the electron will

Faraday's Law states that a voltage is induced in a circuit when there is a changing ___________________ passing through the circuit.

Physics, the Fundamental Science

Describing Motion

Falling Objects and Projectile Motion

Newtons Laws: Explaining Motion

Circular Motion, the Planets, and Gravity

Energy and Oscillations

Momentum and Impulse

Rotational Motion of Solid Objects

The Behavior of Fluids

Temperature and Heat

Heat Engines and the Second Law of Thermodynamics

Electrostatic Phenomena

Electric Circuits

Making Waves

Light Waves and Color

Light and Image Formation

The Structure of the Atom

The Nucleus and Nuclear Energy

Relativity

Beyond Everyday Phenomena

Filters