Ch 21 Physics

0 degrees

At points near Earth's equator, one would expect the magnetic inclination angle to be approximately

the two wires will repel each other

Consider two long, straight, parallel wires, each carring a current I. If the currents move in opposite directions,

the two wires will attract each other

Consider two long, straight, parallel wires, each carrying a current I. If the currents move in the same direction,

the south pole of the magnet

A bar magnet is suspended and allowed to rotate freely. If the magnetic field of Earth is considered to be equivalent to that of a large bar magnet, which pole of the suspended magnet would point toward the magnetic north pole of Earth?

from circles that pass through the wire

A current in a long, straight wire produces a magnetic field. The magnetic field lines..

current

A current in a solenoid coil creates a magnetic field inside the coil. The field strength is directly proportional to the..

number of turns in the loop and the strength of the current

A current in a solenoid with N turns creates a magnetic field inside the solenoid. The magnetic field strength is directly proportional to the

perpendicular to the current

A current-carrying conductor in and perpendicular to a magnetic field experiences a force that is

domain;no

A microscopic magnetic region composed of a group of atoms whose magnetic fields are aligned in a common direction is called a---. In most materials, when these groups are randomly distributed, the subsance will show--- magnetism.

north;attracted

A solenoid is in an upright position on a table. A clockwise current of electrons causes the solenoid to have a --- magnetic pole at its bottom end. If a compass is placed at the top of the solenoid, the north pole of the compass would be----

south;repelled

A solenoid is in an upright position on a table. A counterclockwise current of electrons causes the solenoid to have a---- magnetic pole at its bottom end. If a compass is placed at the top of the solenoid, the north pole of the compass would be------

direction will be west

Electrons move from the south to the north in a wire. What is the direction of the magnetic field at a point directly above the wire?

a compass

How can the magnetic field around a permanent magnet be determined?

east

If a proton is released at the equator and falls toward Earth under the influence of gravity, the magnetic force on the proton will be toward the

proportional to the current and inversely proportional to the distance from the wire

If a wire is carrying a strong, steady current, the magnetic field is

end away from magnet would be north pole

If the head of an iron nail touches a magnet, the nail will become a magnet by induction. If the nail touches the north pole of the magnet, what kind of pole is at the point of the nail? Explain.

line up mainly in one direction

In a magnetized substance, the domain

domain alignment persists after the external magnetic field is removed

In a permanent magnet,

The orientation of domains changes, and the material returns to an unmagnetized state.

In soft magnetic materials such as iron, what happens when an external magnetic field is removed?

straight line

What is the path of an electron moving parallel to a uniform magnetic field?

a circle

What is the path of an electron moving perpendicular to a uniform magnetic field?

causes alignment of the domains in the iron

When an iron rod is inserted into a solenoid coil's center, the magnetic field produced by the current in the loops

close to the poles

Where is the magnitude of the magnetic field around a permanent magnet greatest?

A

Which compass needle orientation in the figure above might correctly describe the magnet's field at that point?

the angle between directions to true north and magnetic

Which describes magnetic declination?

magnetic south

Which magnetic pole is at the geographic North Pole of Earth?

magnetic north

Which magnetic pole is at the geographic South Pole of Earth?

random

Which orientation characterizes the magnetic domains in a nonmagnetized piece of iron?

if wire grasped in right hand with thumb in direction of current fingers curl in direction of magnetic field

Describe how the right hand rule applies to the magnetic field produced by the current in a straight conductor.

the field is inversely proportional to r

The current in a long wire creates a magnetic field in the region around the wire. How is the strength of that field at a given distance, r, from the wire's center related to r?

perpendicular to the current and to the magnetic field

The direction of the force on a current-carrying wire in an external magnetic field is