Electromagnetism Multiple-Choice Practice Questions | AP Physics C Electricity and Magnetism - Grade 9 PDF Download

 Page 1


Section I: Multiple Choice
1. A metal rod of length L is pulled upward with constant velocity v through a uniform magnetic
field B that points out of the plane of the page.
What is the potential difference between points a and b?
(A) 0
(B) BL, with point a at the higher potential
(C) BL, with point b at the higher potential
(D) vBL, with point a at the higher potential
(E) vBL, with point b at the higher potential
2. A circular disk of radius a is rotating at a constant angular speed ? in a uniform magnetic
field, B, which is directed out of the plane of the page.
Determine the induced emf between the center of the disk and the rim.
(A)
(B)
(C)
(D) ? B a
2
(E) 2p? B a
2
3. A conducting rod of length 0.2 m and resistance 10 O between its endpoints slides without
friction along a U-shaped conductor in a uniform magnetic field B of magnitude 0.5 T
perpendicular to the plane of the conductor, as shown in the diagram below.
Page 2


Section I: Multiple Choice
1. A metal rod of length L is pulled upward with constant velocity v through a uniform magnetic
field B that points out of the plane of the page.
What is the potential difference between points a and b?
(A) 0
(B) BL, with point a at the higher potential
(C) BL, with point b at the higher potential
(D) vBL, with point a at the higher potential
(E) vBL, with point b at the higher potential
2. A circular disk of radius a is rotating at a constant angular speed ? in a uniform magnetic
field, B, which is directed out of the plane of the page.
Determine the induced emf between the center of the disk and the rim.
(A)
(B)
(C)
(D) ? B a
2
(E) 2p? B a
2
3. A conducting rod of length 0.2 m and resistance 10 O between its endpoints slides without
friction along a U-shaped conductor in a uniform magnetic field B of magnitude 0.5 T
perpendicular to the plane of the conductor, as shown in the diagram below.
If the rod is moving with velocity v = 3 m/s to the left, what is the magnitude and direction of
the current induced in the rod?
Current Direction
(A) 0.03 A down
(B) 0.03 A up
(C) 0.3 A down
(D) 0.3 A up
(E) 3 A down
4. In the figure below, a small, circular loop of wire (radius r) is placed on an insulating stand
inside a hollow solenoid of radius R. The solenoid has n turns per unit length and carries a
current I. If the current in the solenoid is decreased at a steady rate of a amps/s, determine
the induced emf, e, and the direction of the induced current in the loop.
(A) ; induced current is clockwise
(B) ; induced current is counterclockwise
(C) ; induced current is clockwise
(D) ; induced current is counterclockwise
(E) ; induced current is counterclockwise
5. In the figure below, a permanent bar magnet is pulled upward with a constant velocity
through a loop of wire.
Page 3


Section I: Multiple Choice
1. A metal rod of length L is pulled upward with constant velocity v through a uniform magnetic
field B that points out of the plane of the page.
What is the potential difference between points a and b?
(A) 0
(B) BL, with point a at the higher potential
(C) BL, with point b at the higher potential
(D) vBL, with point a at the higher potential
(E) vBL, with point b at the higher potential
2. A circular disk of radius a is rotating at a constant angular speed ? in a uniform magnetic
field, B, which is directed out of the plane of the page.
Determine the induced emf between the center of the disk and the rim.
(A)
(B)
(C)
(D) ? B a
2
(E) 2p? B a
2
3. A conducting rod of length 0.2 m and resistance 10 O between its endpoints slides without
friction along a U-shaped conductor in a uniform magnetic field B of magnitude 0.5 T
perpendicular to the plane of the conductor, as shown in the diagram below.
If the rod is moving with velocity v = 3 m/s to the left, what is the magnitude and direction of
the current induced in the rod?
Current Direction
(A) 0.03 A down
(B) 0.03 A up
(C) 0.3 A down
(D) 0.3 A up
(E) 3 A down
4. In the figure below, a small, circular loop of wire (radius r) is placed on an insulating stand
inside a hollow solenoid of radius R. The solenoid has n turns per unit length and carries a
current I. If the current in the solenoid is decreased at a steady rate of a amps/s, determine
the induced emf, e, and the direction of the induced current in the loop.
(A) ; induced current is clockwise
(B) ; induced current is counterclockwise
(C) ; induced current is clockwise
(D) ; induced current is counterclockwise
(E) ; induced current is counterclockwise
5. In the figure below, a permanent bar magnet is pulled upward with a constant velocity
through a loop of wire.
Which of the following best describes the direction(s) of the current induced in the loop
(looking down on the loop from above)?
(A) Always clockwise
(B) Always counterclockwise
(C) First clockwise, then counterclockwise
(D) First counterclockwise, then clockwise
(E) No current will be induced in the loop.
6. A square loop of wire (side length = s) surrounds a long, straight wire such that the wire
passes through the center of the square.
Page 4


Section I: Multiple Choice
1. A metal rod of length L is pulled upward with constant velocity v through a uniform magnetic
field B that points out of the plane of the page.
What is the potential difference between points a and b?
(A) 0
(B) BL, with point a at the higher potential
(C) BL, with point b at the higher potential
(D) vBL, with point a at the higher potential
(E) vBL, with point b at the higher potential
2. A circular disk of radius a is rotating at a constant angular speed ? in a uniform magnetic
field, B, which is directed out of the plane of the page.
Determine the induced emf between the center of the disk and the rim.
(A)
(B)
(C)
(D) ? B a
2
(E) 2p? B a
2
3. A conducting rod of length 0.2 m and resistance 10 O between its endpoints slides without
friction along a U-shaped conductor in a uniform magnetic field B of magnitude 0.5 T
perpendicular to the plane of the conductor, as shown in the diagram below.
If the rod is moving with velocity v = 3 m/s to the left, what is the magnitude and direction of
the current induced in the rod?
Current Direction
(A) 0.03 A down
(B) 0.03 A up
(C) 0.3 A down
(D) 0.3 A up
(E) 3 A down
4. In the figure below, a small, circular loop of wire (radius r) is placed on an insulating stand
inside a hollow solenoid of radius R. The solenoid has n turns per unit length and carries a
current I. If the current in the solenoid is decreased at a steady rate of a amps/s, determine
the induced emf, e, and the direction of the induced current in the loop.
(A) ; induced current is clockwise
(B) ; induced current is counterclockwise
(C) ; induced current is clockwise
(D) ; induced current is counterclockwise
(E) ; induced current is counterclockwise
5. In the figure below, a permanent bar magnet is pulled upward with a constant velocity
through a loop of wire.
Which of the following best describes the direction(s) of the current induced in the loop
(looking down on the loop from above)?
(A) Always clockwise
(B) Always counterclockwise
(C) First clockwise, then counterclockwise
(D) First counterclockwise, then clockwise
(E) No current will be induced in the loop.
6. A square loop of wire (side length = s) surrounds a long, straight wire such that the wire
passes through the center of the square.
If the current in the wire is I, determine the current induced in the square loop.
(A)
(B)
(C)
(D)
(E) 0
Questions 7-9
A circuit contains a solenoid of inductance L in series with a resistor of resistance R and a battery
with terminal voltage e. At time t = 0, a switch is closed and the circuit is completed.
7. How long does it take for the current to reach  of its maximum (steady-state) value?
(A) (ln 4)( L/ R)
(B) (ln )(L/ R)
(C) (ln )(L/ R)
(D) (ln )(R/ L)
(E) (ln 4)( R/ L)
Page 5


Section I: Multiple Choice
1. A metal rod of length L is pulled upward with constant velocity v through a uniform magnetic
field B that points out of the plane of the page.
What is the potential difference between points a and b?
(A) 0
(B) BL, with point a at the higher potential
(C) BL, with point b at the higher potential
(D) vBL, with point a at the higher potential
(E) vBL, with point b at the higher potential
2. A circular disk of radius a is rotating at a constant angular speed ? in a uniform magnetic
field, B, which is directed out of the plane of the page.
Determine the induced emf between the center of the disk and the rim.
(A)
(B)
(C)
(D) ? B a
2
(E) 2p? B a
2
3. A conducting rod of length 0.2 m and resistance 10 O between its endpoints slides without
friction along a U-shaped conductor in a uniform magnetic field B of magnitude 0.5 T
perpendicular to the plane of the conductor, as shown in the diagram below.
If the rod is moving with velocity v = 3 m/s to the left, what is the magnitude and direction of
the current induced in the rod?
Current Direction
(A) 0.03 A down
(B) 0.03 A up
(C) 0.3 A down
(D) 0.3 A up
(E) 3 A down
4. In the figure below, a small, circular loop of wire (radius r) is placed on an insulating stand
inside a hollow solenoid of radius R. The solenoid has n turns per unit length and carries a
current I. If the current in the solenoid is decreased at a steady rate of a amps/s, determine
the induced emf, e, and the direction of the induced current in the loop.
(A) ; induced current is clockwise
(B) ; induced current is counterclockwise
(C) ; induced current is clockwise
(D) ; induced current is counterclockwise
(E) ; induced current is counterclockwise
5. In the figure below, a permanent bar magnet is pulled upward with a constant velocity
through a loop of wire.
Which of the following best describes the direction(s) of the current induced in the loop
(looking down on the loop from above)?
(A) Always clockwise
(B) Always counterclockwise
(C) First clockwise, then counterclockwise
(D) First counterclockwise, then clockwise
(E) No current will be induced in the loop.
6. A square loop of wire (side length = s) surrounds a long, straight wire such that the wire
passes through the center of the square.
If the current in the wire is I, determine the current induced in the square loop.
(A)
(B)
(C)
(D)
(E) 0
Questions 7-9
A circuit contains a solenoid of inductance L in series with a resistor of resistance R and a battery
with terminal voltage e. At time t = 0, a switch is closed and the circuit is completed.
7. How long does it take for the current to reach  of its maximum (steady-state) value?
(A) (ln 4)( L/ R)
(B) (ln )(L/ R)
(C) (ln )(L/ R)
(D) (ln )(R/ L)
(E) (ln 4)( R/ L)
8. When the current reaches its maximum value, how much energy is stored in the magnetic
field of the solenoid?
(A) L
2
e
2
/(4 R
2
)
(B) L
2
e
2
/(2 R
2
)
(C) Le
2
/(4 R
2
)
(D) Le
2
/(2 R
2
)
(E) 0
9. When the current reaches its maximum value, what is the total magnetic flux through the
solenoid?
(A) Le
(B) Le/ R
(C) e/( RL)
(D) RL/e
(E) 0
 
10. Which one of Maxwell’s equations states that a changing electric field produces a magnetic
field?
(A) Gauss’s law
(B) Gauss’s law for magnetism
(C) Biot–Savart law
(D) Ampere–Maxwell law
(E) Faraday’s law