Problem Set 08

Physics 2220 – Module 08 Homework
01.
An electron moves along the z-axis with vz = 2.0 × 107 m/s. As it passes the origin, what are the strength
and direction of the magnetic field at the (x, y, z) positions of (a) (1 cm, 0 cm, 0 cm), (b) (0 cm, 0 cm, 1
cm), and (c) (0 cm, 1 cm, 1 cm)?
02.
The magnetic field at the center of a 1.0-cm-diameter loop is 2.5 mT.
(a)
(b)
What is the current in the loop?
A long straight wire caries the same current you found in part (a). At what distance from the wire
is the magnetic field of 2.5 mT?
03.
What are the magnetic field strength and direction at points a to c in the figure??
04.
The Earth's magnetic dipole moment is 8.0 × 1022 A m2.
(a)
(b)
What is the magnetic field strength on the surface of the Earth at the Earth's north magnetic
pole? How does this compare to the value in Table 32.1? You can assume that the current loop
is deep inside the Earth.
Astronauts discover an earth-sized planet without a magnetic field. To create a magnetic field
with the same strength as Earth's, the propose running a current though a wire around the
equator. What size current would be needed?
05.
What is the line integral of B between points i and f in the figure?
06.
The value of the line integral of B around the closed path in the figure is 1.38 × 10 -5 T m. What are the
direction (in or out of the page) and magnitude of I 3?
07.
The two 10-cm-long parallel wires in the figure are separated by 5.0 mm. For what value of the resistor
R will the force between the two wires be 5.4 × 10-5 N?