Download Quiz 6 (Due date March 04)

Print Assignment: ::false
1 of 5
CH29
http://edugen.wiley.com/edugen/shared/assignment/test/agprint.uni
Please ignore the Simulation problems.
These are for student with WP online access
Start Date:
25 Feb 2009 at 01:00 PM
Due Date:
4 Mar 2009 at 11:00 PM
Student Access after Due Date:
Graded:
Yes. View With Assistance
Yes
*Chapter 29, Problem 5 GO
In the figure, two circular arcs have radii a = 13.0 cm and b = 10.4 cm, subtend angle θ = 78.0°, carry current
i = 0.433 A, and share the same center of curvature P. What are the (a) magnitude and (b) direction (answer in or
out to mean into or out of the plane of the figure) of the net magnetic field at P?
(a) Number
*1
Units
(b)
the tolerance is +/-5%
*Chapter 29, Problem 16 GO
The figure shows, in cross section, four thin wires that are parallel, straight, and very long. They carry identical
currents of i = 3.95 A in the directions indicated. Initially all four wires are at distance d = 15.3 cm from the origin of
the coordinate system, where they create a net magnetic field
the x axis in order to rotate
Number
. To what value of x must you move wire 1 along
counterclockwise by 30°?
Units
the tolerance is +/-5%
*Chapter 29, Problem 39 GO
In the figure, four long straight wires are perpendicular to the page, and their cross sections form a square of edge
2/25/2009 1:17 PM
Print Assignment: ::false
2 of 5
http://edugen.wiley.com/edugen/shared/assignment/test/agprint.uni
length a = 14.0 cm. Each wire carries 7.00 A, and the currents are out of the page in wires 1 and 4 and into the page
in wires 2 and 3. In unit-vector notation, what is the net magnetic force per meter of wire length on wire 4?
Number:
*1
+
*2
Unit:
Answer *1: the tolerance is +/-5%
Answer *2: the tolerance is +/-5%
*Chapter 29, Problem 52
A solenoid that is 123 cm long has a radius of 1.75 cm and a winding of 994 turns; it carries a current of 3.29 A.
Calculate the magnitude of the magnetic field inside the solenoid.
Number
Units
the tolerance is +/-5%
*Chapter 29, Problem 60
In the figure 29-74, current i = 61.6 mA is set up in a loop having two radial lengths and two semicircles of radii a =
7.21 cm and b = 18.7 cm with a common center P. What are the (a) magnitude of the magnetic field at P and (b)
magnitude of the loop's magnetic dipole moment?
Figure 29-74
(a) Number
Units
(b) Number
Units
Answer a1: the tolerance is +/-5%
Answer b1: the tolerance is +/-5%
*Chapter 29, Problem 69
A bare copper wire of 6.0 mm in diameter can carry a current of 55 A without overheating. For this current, what is
the magnitude of the magnetic field (in mT) at the surface of the wire?
Number
Units
the tolerance is +/-5%
2/25/2009 1:17 PM
Print Assignment: ::false
3 of 5
http://edugen.wiley.com/edugen/shared/assignment/test/agprint.uni
*Simulation: Magnetic Field from a Long Straight Wire, Question 2
Using the simulation answer the following questions.
(a) Set the sliders so the two currents have non-zero values of different magnitude.
Which wire experiences the force per unit length with the largest magnitude?
The wire with the larger magnitude of current.
The wire with the smaller magnitude of current.
It could be either of the above - it depends whether the current directions are the same or opposite.
None of the above - the wires experience forces per unit length of equal magnitude.
(b) If you reverse the direction of the current in the left wire, and reverse the direction of the current in the right
wire, what happens to the directions of the forces experienced by the two wires?
It could be either of the above - it depends whether the two currents are originally both in the same direction
or in opposite directions.
Nothing.
The forces reverse direction.
(c) Now set the current in the left wire to +1 A and the current in the right wire to +4 A. At what location on the
x-axis a finite distance from the wires is the net magnetic field equal to zero?
m
the tolerance is +/-5%
(d) Now set the current in the left wire to +1 A and the current in the right wire to -4 A. At what location on the
x-axis a finite distance from the wires is the net magnetic field equal to zero? Express your answer with three
significant figures.
m
the tolerance is +/-5%
Simulation: Magnetic Field from a Solenoid, Question 2
In this simulation, you can examine the magnetic field created by the current in a solenoid, which is a cylindrical coil
of wire. Instead of using a spiral-shaped coil, the simulation approximates the coil with a stack of seven single loops.
The plane of each loop is parallel to the x-z plane, with a radius of either 60 cm or 25 cm, and the displayed field is in
the x-y plane.
The parallel-plate capacitor is the standard way to create a uniform electric field, while a current-carrying solenoid is a
great way to create a uniform magnetic field, although the electric field is only perfectly uniform in the ideal case
when the plates are infinitely large and the magnetic field is only perfectly uniform in the ideal case when the
solenoid is made from closely packed loops that extend to infinity in the direction parallel to the axis of the solenoid.
(a) Which of the following statements correctly compare the ideal parallel-plate capacitor to the ideal solenoid? Select
all that apply.
A charged particle launched into the uniform field between the plates of the parallel-plate capacitor will follow
a parabolic path. The same is true for a charged particle launched into the uniform magnetic field inside the
solenoid.
In both ideal devices the fields are uniform inside the devices and zero outside.
The direction of the uniform electric field in the capacitor is parallel to the plates making up the capacitor,
while the direction of the uniform magnetic field is parallel to the axis of the solenoid.
The electric field in the capacitor is produced by static charges, while the magnetic field in the solenoid is
produced by moving charges.
Doubling the magnitude of the charge on each plate of the ideal capacitor doubles the electric field. Doubling
the current in each loop of the solenoid doubles the magnetic field.
2/25/2009 1:17 PM
Print Assignment: ::false
4 of 5
http://edugen.wiley.com/edugen/shared/assignment/test/agprint.uni
In the ideal capacitor changing the distance between the plates does not affect the electric field. In the ideal
solenoid changing the radius of the solenoid does not affect the magnetic field.
(b) Which of the following statements correctly describe what happens with the non-ideal solenoid shown in the
simulation? Select all that apply.
Increasing the separation between the coils of the solenoid increases the magnitude of the magnetic field at
the center of the solenoid.
As long as the current is non-zero, changing the magnitude of the current without changing its sign results in
a change in the magnitude of the magnetic field at every point, but no change in the direction of the field at
any point. (Exceptions to this are points where the field is zero, which remain at zero.)
Increasing the size of the loops making up the solenoid increases the magnitude of the magnetic field at the
center of the solenoid.
Reversing the direction of the current without changing its magnitude results in the magnetic field reversing
at every point, but no change in the magnitude of the field at any point.
Staying inside the solenoid, the magnetic field generally decreases in magnitude as you move away from the
exact center of the solenoid along a direction perpendicular to the axis of the solenoid (moving along the
x-axis would be such a direction, for instance).
The magnetic field generally decreases in magnitude as you move away from the exact center of the solenoid
along the solenoid's axis (the y-axis, in this case).
Test Bank, Question 10
The magnetic field outside a long straight current-carrying wire depends on the distance R from the wire axis
according to:
R
1/R
1/R2
1/R3
1/R3/2
Test Bank, Question 20
Two parallel long wires carry the same current and repel each other with a force F per unit length. If both these
currents are doubled and the wire separation tripled, the force per unit length becomes:
2F/9
4F/9
2F/3
4F/3
6F
Test Bank, Question 30
If the magnetic field
is uniform over the area bounded by a circle with a radius R, the net current through the
circle is:
0
2/25/2009 1:17 PM
Print Assignment: ::false
5 of 5
2
http://edugen.wiley.com/edugen/shared/assignment/test/agprint.uni
RB
0
R2B/
RB/2
0
2RB/
0
0
2/25/2009 1:17 PM