Question 1

A rectangular loop of wire is placed midway between two long straight parallel conductors as shown.The conductors carry currents i1 and i2 as indicated.If i1 is increasing and i2 is constant, then the induced current in the loop is:

Accepted Answer

A)  zero
B)  clockwise
C)  counterclockwise
D)  depends on i1 - i2
E)  depends on i1 + i2 C

Question 2

A single loop of wire with a radius of 7.5 cm rotates about a diameter in a uniform magnetic field of 1.6 T.To produce a maximum emf of 1.0 V, it should rotate at:

Accepted Answer

A)  0 rad/s
B)  2.7 rad/s
C)  5.6 rad/s
D)  35 rad/s
E)  71 rad/s D

Question 3

A 10-turn ideal solenoid has an inductance of 3.5 mH.When the solenoid carries a current of 2.0 A the magnetic flux through each turn is:

Accepted Answer

A)  0 Wb
B)  3.5 * 10-4 Wb
C)  7.0 * 10-4 Wb
D)  7.0 *10-3 Wb
E)  7.0 *10-2 Wb C

Question 4

A 10 turn conducting loop with a radius of 3.0 cm spins at 60 revolutions per second in a magnetic field of 0.50 T.The maximum emf generated is:

Accepted Answer

A)  0.014 V
B)  0.085 V
C)  0.53 V
D)  0.85 V
E)  5.3 V

Question 5

A uniform magnetic field makes an angle of 30 ° with the z axis.If the magnetic flux through a 1.0 m2 portion of the xy plane is 5.0 Wb then the magnetic flux through a 2.0 m2 portion of the same plane is:

Accepted Answer

A)  2.5 Wb
B)  4.3 Wb
C)  5.0 Wb
D)  5.8 Wb
E)  10 Wb

Question 6

Suppose this page is perpendicular to a uniform magnetic field and the magnetic flux through it is 5.0 Wb.If the page is turned by 30°around an edge the flux through it will be:

Accepted Answer

A)  2.5 Wb
B)  4.3 Wb
C)  5.0 Wb
D)  5.8 Wb
E)  10 Wb

Question 7

A 0.20-cm radius cylinder, 3.0 cm long, is wrapped with wire to form an inductor.At the instant the magnetic field in the interior is 5.0 mT, the energy stored in the field is:

Accepted Answer

A)  0 J
B)  3.8*10-6 J
C)  7.5 *10-6 J
D)  7.5*10-4 J
E)  9.9 J

Question 8

A cylindrical region of radius R contains a uniform magnetic field, parallel to its axis, with magnitude that is changing linearly with time.If r is the radial distance from the cylinder axis, the magnitude of the induced electric field outside the cylinder is proportional to:

Accepted Answer

A)  R
B)  r
C)  r2
D)  1/r
E)  1/r2

Question 9

A copper hoop is held in a vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction.The largest induced emf is produced when the hoop is:

Accepted Answer

A)  rotated about a north-south axis
B)  rotated about an east-west axis
C)  moved rapidly, without rotation, toward the east
D)  moved rapidly, without rotation, toward the south
E)  moved rapidly, without rotation, toward the northwest

Question 10

The magnetic flux ΦB through a surface:

Accepted Answer

A)  is the amount of magnetic field piercing the surface.
B)  is the magnetic field multiplied by the area.
C)  does not depend on the area involved.
D)  is the line integral of the magnetic field around the edge of the surface.
E)  is the amount of magnetic field skimming along the surface.

Question 11

An inductance L and a resistance R are connected in series to an ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.The energy stored in the inductor is a maximum:

Accepted Answer

A)  just after the switch is closed
B)  at the time t = L/R after the switch is closed
C)  at the time t = L/R2 after the switch is closed
D)  at the time t = 2L/R after the switch is closed
E)  a long time after the switch is closed

Question 12

An inductance L, resistance R, and ideal battery of emf  are wired in series.A switch in the circuit is closed at time t = 0, at which time the current is zero.At any later time t the potential difference across the resistor is given by:

Accepted Answer

A)   -Lt/R)  
B)     e-Lt/R 
C)     (1 + e-Rt/L)  
D)     e-Rt/L 
E)     (1 - e-Rt/L) " class="answers-bank-image d-inline" rel="preload" > (1 - e-Lt/R) 
B)   -Lt/R)  
B)     e-Lt/R 
C)     (1 + e-Rt/L)  
D)     e-Rt/L 
E)     (1 - e-Rt/L) " class="answers-bank-image d-inline" rel="preload" > e-Lt/R
C)   -Lt/R)  
B)     e-Lt/R 
C)     (1 + e-Rt/L)  
D)     e-Rt/L 
E)     (1 - e-Rt/L) " class="answers-bank-image d-inline" rel="preload" > (1 + e-Rt/L) 
D)   -Lt/R)  
B)     e-Lt/R 
C)     (1 + e-Rt/L)  
D)     e-Rt/L 
E)     (1 - e-Rt/L) " class="answers-bank-image d-inline" rel="preload" > e-Rt/L
E)   -Lt/R)  
B)     e-Lt/R 
C)     (1 + e-Rt/L)  
D)     e-Rt/L 
E)     (1 - e-Rt/L) " class="answers-bank-image d-inline" rel="preload" > (1 - e-Rt/L)

Question 13

A circular loop of wire rotates about a diameter in a magnetic field that is perpendicular to the axis of rotation.Looking in the direction of the field at the loop the induced current is:

Accepted Answer

A)  always clockwise
B)  always counterclockwise
C)  clockwise in the lower half of the loop and counterclockwise in the upper half
D)  clockwise in the upper half of the loop and counterclockwise in the lower half
E)  sometimes clockwise and sometimes counterclockwise

Question 14

At a particular instant of time the total magnetic flux through a stationary conducting loop is less in magnitude than the flux associated with an externally applied field.This might occur because:

Accepted Answer

A)  the applied field is normal to the loop and increasing in magnitude
B)  the applied field is normal to the loop and decreasing in magnitude
C)  the applied field is parallel to the plane of the loop and increasing in magnitude
D)  the applied field is parallel to the plane of the loop and decreasing in magnitude
E)  the applied field is tangent to the loop

Question 15

An electric field is associated with every:

Accepted Answer

A)  magnetic field
B)  time-dependent magnetic field
C)  position-dependent magnetic field
D)  object moving in a magnetic field
E)  conductor moving in a magnetic field

Question 16

The four wire loops shown have edge lengths of either L, 2L, or 3L.They will move with the same speed into a region of uniform magnetic field  directed out of the page.Rank them according to the maximum magnitude of the induced emf, least to greatest.

Accepted Answer

A)  1 and 2 tie, then 3 and 4 tie
B)  3 and 4 tie, then 1 and 2 tie
C)  4, then 2 and 3 tie, then 1
D)  1, then 2 and 3 tie, then 4
E)  1, 2, 3, 4

Question 17

A square loop of wire lies in the plane of the page.A decreasing magnetic field is directed into the page.The induced current in the loop is:

Accepted Answer

A)  counterclockwise
B)  clockwise
C)  zero
D)  up the left edge and from right to left along the top edge
E)  through the middle of the page

Question 18

The stored energy in an inductor:

Accepted Answer

A)  depends, in sign, upon the direction of the current
B)  depends on the rate of change of current
C)  is proportional to the square of the inductance
D)  has units J/H
E)  is none of the above

Question 19

As a loop of wire with a resistance of 10 $\Omega$moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5.0 mJ/s.The induced current in the loop is:

Accepted Answer

A)  0 A
B)  2.0 mA
C)  2.8 mA
D)  22 mA
E)  cannot be calculated from the given data

Question 20

A long straight wire is in the plane of a rectangular conducting loop.The straight wire carries an increasing current in the direction shown.The current in the loop is:

Accepted Answer

A)  zero
B)  clockwise
C)  counterclockwise
D)  clockwise in the left side and counterclockwise in the right side
E)  counterclockwise in the left side and clockwise in the right side

Exam 30: Induction and Inductance

A rectangular loop of wire is placed midway between two long straight parallel conductors as shown.The conductors carry currents i₁ and i₂ as indicated.If i₁ is increasing and i₂ is constant, then the induced current in the loop is:

A single loop of wire with a radius of 7.5 cm rotates about a diameter in a uniform magnetic field of 1.6 T.To produce a maximum emf of 1.0 V, it should rotate at:

A 10-turn ideal solenoid has an inductance of 3.5 mH.When the solenoid carries a current of 2.0 A the magnetic flux through each turn is:

A 10 turn conducting loop with a radius of 3.0 cm spins at 60 revolutions per second in a magnetic field of 0.50 T.The maximum emf generated is:

A uniform magnetic field makes an angle of 30 ° with the z axis.If the magnetic flux through a 1.0 m² portion of the xy plane is 5.0 Wb then the magnetic flux through a 2.0 m² portion of the same plane is:

Suppose this page is perpendicular to a uniform magnetic field and the magnetic flux through it is 5.0 Wb.If the page is turned by 30°around an edge the flux through it will be:

A 0.20-cm radius cylinder, 3.0 cm long, is wrapped with wire to form an inductor.At the instant the magnetic field in the interior is 5.0 mT, the energy stored in the field is:

A cylindrical region of radius R contains a uniform magnetic field, parallel to its axis, with magnitude that is changing linearly with time.If r is the radial distance from the cylinder axis, the magnitude of the induced electric field outside the cylinder is proportional to:

A copper hoop is held in a vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction.The largest induced emf is produced when the hoop is:

The magnetic flux Φ_B through a surface:

An inductance L and a resistance R are connected in series to an ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.The energy stored in the inductor is a maximum:

An inductance L, resistance R, and ideal battery of emf are wired in series.A switch in the circuit is closed at time t = 0, at which time the current is zero.At any later time t the potential difference across the resistor is given by:

A circular loop of wire rotates about a diameter in a magnetic field that is perpendicular to the axis of rotation.Looking in the direction of the field at the loop the induced current is:

At a particular instant of time the total magnetic flux through a stationary conducting loop is less in magnitude than the flux associated with an externally applied field.This might occur because:

An electric field is associated with every:

The four wire loops shown have edge lengths of either L, 2L, or 3L.They will move with the same speed into a region of uniform magnetic field directed out of the page.Rank them according to the maximum magnitude of the induced emf, least to greatest.

A square loop of wire lies in the plane of the page.A decreasing magnetic field is directed into the page.The induced current in the loop is:

The stored energy in an inductor:

As a loop of wire with a resistance of 10 $\Omega$ moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5.0 mJ/s.The induced current in the loop is:

A long straight wire is in the plane of a rectangular conducting loop.The straight wire carries an increasing current in the direction shown.The current in the loop is:

Exam 30: Induction and Inductance

A rectangular loop of wire is placed midway between two long straight parallel conductors as shown.The conductors carry currents i1 and i2 as indicated.If i1 is increasing and i2 is constant, then the induced current in the loop is:

A single loop of wire with a radius of 7.5 cm rotates about a diameter in a uniform magnetic field of 1.6 T.To produce a maximum emf of 1.0 V, it should rotate at:

A 10-turn ideal solenoid has an inductance of 3.5 mH.When the solenoid carries a current of 2.0 A the magnetic flux through each turn is:

A 10 turn conducting loop with a radius of 3.0 cm spins at 60 revolutions per second in a magnetic field of 0.50 T.The maximum emf generated is:

A uniform magnetic field makes an angle of 30 ° with the z axis.If the magnetic flux through a 1.0 m2 portion of the xy plane is 5.0 Wb then the magnetic flux through a 2.0 m2 portion of the same plane is:

Suppose this page is perpendicular to a uniform magnetic field and the magnetic flux through it is 5.0 Wb.If the page is turned by 30°around an edge the flux through it will be:

A 0.20-cm radius cylinder, 3.0 cm long, is wrapped with wire to form an inductor.At the instant the magnetic field in the interior is 5.0 mT, the energy stored in the field is:

A cylindrical region of radius R contains a uniform magnetic field, parallel to its axis, with magnitude that is changing linearly with time.If r is the radial distance from the cylinder axis, the magnitude of the induced electric field outside the cylinder is proportional to:

A copper hoop is held in a vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction.The largest induced emf is produced when the hoop is:

The magnetic flux ΦB through a surface:

An inductance L and a resistance R are connected in series to an ideal battery.A switch in the circuit is closed at time t = 0, at which time the current is zero.The energy stored in the inductor is a maximum:

An inductance L, resistance R, and ideal battery of emf are wired in series.A switch in the circuit is closed at time t = 0, at which time the current is zero.At any later time t the potential difference across the resistor is given by:

A circular loop of wire rotates about a diameter in a magnetic field that is perpendicular to the axis of rotation.Looking in the direction of the field at the loop the induced current is:

At a particular instant of time the total magnetic flux through a stationary conducting loop is less in magnitude than the flux associated with an externally applied field.This might occur because:

An electric field is associated with every:

The four wire loops shown have edge lengths of either L, 2L, or 3L.They will move with the same speed into a region of uniform magnetic field directed out of the page.Rank them according to the maximum magnitude of the induced emf, least to greatest.

A square loop of wire lies in the plane of the page.A decreasing magnetic field is directed into the page.The induced current in the loop is:

The stored energy in an inductor:

As a loop of wire with a resistance of 10 Ω\OmegaΩ moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5.0 mJ/s.The induced current in the loop is:

A long straight wire is in the plane of a rectangular conducting loop.The straight wire carries an increasing current in the direction shown.The current in the loop is:

A rectangular loop of wire is placed midway between two long straight parallel conductors as shown.The conductors carry currents i₁ and i₂ as indicated.If i₁ is increasing and i₂ is constant, then the induced current in the loop is:

A uniform magnetic field makes an angle of 30 ° with the z axis.If the magnetic flux through a 1.0 m² portion of the xy plane is 5.0 Wb then the magnetic flux through a 2.0 m² portion of the same plane is:

The magnetic flux Φ_B through a surface:

As a loop of wire with a resistance of 10 $\Omega$ moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5.0 mJ/s.The induced current in the loop is: