Clicker Question
Recall that
∫
 
E ⋅ dA = qenc /ε0
What is the total flux of the magnetic field through any
closed surface?
 
∫ B ⋅ dA = ?
A) zero
B) Ienc times a positive constant
C) -Ienc times a positive constant
Clicker Question
Recall that
∫
 
E ⋅ dA = qenc /ε0
What is the total flux of the magnetic field through any
closed surface?
 
∫ B ⋅ dA = ?
A) zero
B) Ienc times a positive constant
C) -Ienc times a positive constant
Clicker Question
The figure shows, in cross
section, three conductors that
carry currents perpendicular to
the plane of the figure.
If the currents I1, I2, and I3 all
have the same magnitude, for
which path(s) is the line integral
of the magnetic field equal to
zero?
A. path a only
B. paths a and c
C. paths b and d
D. paths a, b, c, and d
E. The answer depends on whether the integral goes
clockwise or counterclockwise around the path.
Clicker Question
The figure shows, in cross
section, three conductors that
carry currents perpendicular to
the plane of the figure.
If the currents I1, I2, and I3 all
have the same magnitude, for
which path(s) is the line integral
of the magnetic field equal to
zero?
A. path a only
B. paths a and c
C. paths b and d
D. paths a, b, c, and d
E. The answer depends on whether the integral goes
clockwise or counterclockwise around the path.
Clicker Question
Consider the coaxial cable. In such a cable, a current I runs in one
direction along the outer hollow conducting cylinder and is
spread evenly over the cylinder’s cross sectional area. An equal
current runs in the opposite direction along the central wire.
How does the magnitude of B outside the coax cable depend on
distance r from the central axis of the cable?
A) B proportional to 1/r
B) B is proportional to 1/r2
C) B is constant and non-zero
D) B is zero
central
wire
outer
hollow
conductor
Clicker Question
Consider the coaxial cable. In such a cable, a current I runs in one
direction along the outer hollow conducting cylinder and is
spread evenly over the cylinder’s cross sectional area. An equal
current runs in the opposite direction along the central wire.
How does the magnitude of B outside the coax cable depend on
distance r from the central axis of the cable?
A) B proportional to 1/r
B) B is proportional to 1/r2
C) B is constant and non-zero
D) B is zero
central
wire
outer
hollow
conductor
Figure 29.6
Figure 29.14
Clicker Question
A circular loop of wire is in a
region of spatially uniform
magnetic field. The magnetic
field is directed into the plane of
the figure. If the magnetic field
magnitude is constant,
A. the induced emf is clockwise.
B. the induced emf is counterclockwise.
C. the induced emf is zero.
D. The answer depends on the strength of the
field.
Clicker Question
A circular loop of wire is in a
region of spatially uniform
magnetic field. The magnetic
field is directed into the plane of
the figure. If the magnetic field
magnitude is constant,
A. the induced emf is clockwise.
B. the induced emf is counterclockwise.
C. the induced emf is zero.
D. The answer depends on the strength of the
field.
Clicker Question
A circular loop of wire is in a
region of spatially uniform
magnetic field. The magnetic field
is directed into the plane of the
figure. If the magnetic field
magnitude is decreasing,
A. the induced emf is clockwise.
B. the induced emf is counterclockwise.
C. the induced emf is zero.
D. The answer depends on the strength of the field.
Clicker Question
A circular loop of wire is in a
region of spatially uniform
magnetic field. The magnetic field
is directed into the plane of the
figure. If the magnetic field
magnitude is decreasing,
A. the induced emf is clockwise.
B. the induced emf is counterclockwise.
C. the induced emf is zero.
D. The answer depends on the strength of the field.
Clicker Question
The wire coil is in a uniform magnetic field and is being
squeezed as shown. While the coil is being squeezed,
the direction of the induced emf in the coil is:
A) Clockwise
B) Counterclockwise
C) Zero
D) None of the above
Clicker Question
The wire coil is in a uniform magnetic field and is being
squeezed as shown. While the coil is being squeezed,
the direction of the induced emf in the coil is:
A) Clockwise
B) Counterclockwise
C) Zero
D) None of the above
Clicker Question
A flexible loop of wire lies in a
uniform magnetic field of
magnitude B directed into the
plane of the picture. The loop
is pulled as shown, reducing its
area. The induced current
A. flows downward through resistor R and is proportional to B.
B. flows upward through resistor R and is proportional to B.
C. flows downward through resistor R and is proportional to B2.
D. flows upward through resistor R and is proportional to B2.
E. none of the above
Clicker Question
A flexible loop of wire lies in a
uniform magnetic field of
magnitude B directed into the
plane of the picture. The loop
is pulled as shown, reducing its
area. The induced current
A. flows downward through resistor R and is proportional to B.
B. flows upward through resistor R and is proportional to B.
C. flows downward through resistor R and is proportional to B2.
D. flows upward through resistor R and is proportional to B2.
E. none of the above
Clicker Question
The rectangular loop of wire is being
moved to the right at constant velocity.
A constant current I flows in the long
straight wire in the direction shown.
The current induced in the loop is
A. clockwise and proportional to I.
B. counterclockwise and proportional to I.
C. clockwise and proportional to I2.
D. counterclockwise and proportional to I2.
E. zero.
Clicker Question
The rectangular loop of wire is being
moved to the right at constant velocity.
A constant current I flows in the long
straight wire in the direction shown.
The current induced in the loop is
A. clockwise and proportional to I.
B. counterclockwise and proportional to I.
C. clockwise and proportional to I2.
D. counterclockwise and proportional to I2.
E. zero.