Mastering Physics: Chapter 24

Magnetic compasses reportedly were first used for navigation by Chinese sailors. Australian aborigines. Aristotle. none of the above

Chinese sailors.

Solar winds headed in Earth's direction are deviated mainly by Earth's magnetic field. Earth's radiation belts. the upper atmosphere. the troposphere

Earth's magnetic field.

Surrounding every magnet is an electric field. a magnetic field. both of these neither of these

a magnetic field.

The magnetic fields of a pair of nearby magnets can cannot add or subtract. add or subtract by vector rules. only add.

add or subtract by vector rules.

Magnetic fields are produced by all moving electrical charges. a tiny fraction of moving electrical charges. most moving electrical charges.

all moving electrical charges.

When current reverses direction in a wire, the surrounding magnetic field expands. contracts. also reverses direction. becomes momentarily stronger.

also reverses direction.

A current-carrying coil of wire is a magplane in the making. an electromagnet. a superconducting magnet. a superconductor

an electromagnet.

In general, a common magnet has one pole. at least two poles. only two poles

at least two poles.

The direction of the force exerted on a moving charge in a magnetic field is at right angles to the direction of the motion. in the direction of the motion. opposite its motion.

at right angles to the direction of the motion.

Like kinds of magnetic poles repel while unlike kinds of magnetic poles repel also. attract. may attract or repel

attract.

When a current-carrying wire is bent into a loop, its magnetic field inside the loop cancels. weakens. becomes concentrated. none of the above

becomes concentrated.

A current-carrying wire in a magnetic field may be deflected. may experience a force. both of these neither of these

both of these

An electron beam directed through a magnetic field may experience a force. may be deflected. both of these neither of these

both of these

Magnetism is due to the motion of electrons as they spin on their axes. move around the nucleus. both of these neither of these

both of these

No net force acts on a loop of wire in a magnetic field when no current is in the loop. no magnetic field lines pass through the loop. both of these neither of these

both of these

Surrounding every moving electron is a magnetic field. an electric field. both of these neither of these

both of these

The force that acts between a pair of electrically-charged particles depends on separation distance. magnitude of charge. both of these neither of these

both of these

The force that acts between a pair of magnetic poles depends on magnetic pole strength. separation distance. both of these neither of these

both of these

Which force field can accelerate an electron? magnetic field electric field both of these neither of these

both of these

Whereas electric charges can be isolated, magnetic poles gather in clusters. cannot. can also. none of the above

cannot.

Magnetic field lines about a current-carrying wire extend radially from the wire. circle the wire in closed loops. both of these neither of these

circle the wire in closed loops.

The shape of a magnetic field surrounding a current-carrying conductor is circular. consistent with the inverse-square law. radial. all of these neither of these

circular.

Magnetic field strength about a magnet is strongest where magnetic field lines are closer together. more spread. most curved. straightest.

closer together.

When an electron passes through the magnetic field of a horseshoe magnet, the electron's speed is increased. direction is changed. both of these neither of these

direction is changed.

Which force field can increase a moving electron's speed? magnetic field electric field both of these neither of these

electric field

Compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is relatively small. equally huge. inversely proportional to their masses.

equally huge.

Magnet A has twice the magnetic field strength of Magnet B and at a certain distance pulls on magnet B with a force of 100 N. The amount of force that magnet A exerts on magnet B is exactly 100 N. at or about 50 N. need more information

exactly 100 N.

Over geologic history the Earth's magnetic field has increased in strength exponentially. is unknown. has reversed direction many times. has been relatively stable.

has reversed direction many times.

If you break a bar magnet in half you'll have two magnets. destroy its magnetic properties. have two and a half magnets. none of the above

have two magnets.

Place an iron rod inside a current-carrying coil of wire and you increase the strength of the electromagnet. have a superconducting magnet. a magplane in the making.

increase the strength of the electromagnet.

Magnetic domains normally occur in silver. iron. copper. all of the above none of the above

iron.

Into which stable force field can a proton be placed at rest without being acted upon by a force? magnetic field electric field both of these neither of these

magnetic field

The source of all magnetism is moving electric charge. tiny domains of aligned atoms. tiny pieces of iron. ferromagnetic materials. none of the above

moving electric charge.

The end of a compass needle that points to the south pole of a magnet is the south pole. north pole. both of these

north pole.

The conventional direction of magnetic field lines outside a magnet are from south to north. north to south. either way

north to south.

A beam of electrons can pass through a magnetic field without being deflected if the direction of the beam is perpendicular to the field lines. parallel to the field lines. none of these

parallel to the field lines.

A beam of electrons passing through a magnetic field experiences maximum deflection if the direction of the beam is parallel to the field lines. perpendicular to the field lines. none of these

perpendicular to the field lines.

The force a magnetic field exerts on a current-carrying wire is maximum when the wire is oriented parallel to the magnetic field. perpendicular to the magnetic field. either of these neither of these

perpendicular to the magnetic field.

The force exerted on an electron moving in a magnetic field is maximum when the electron moves parallel to the magnetic field. perpendicular to the magnetic field. either of these neither of these

perpendicular to the magnetic field.

If a magnet produces a force on a current-carrying wire, the wire may or may not produce a force on the magnet. produces a force on the magnet. none of these

produces a force on the magnet.

Refrigerator magnets are typically long range. short range. none of these

short range.

As the number of loops in a current-carrying wire is increased, the stronger the enclosed magnetic field. more spread out is the magnetic field. weaker the current. greater the back emf.

stronger the enclosed magnetic field.

An iron rod becomes magnetic when its atoms are aligned. opposite ions accumulate at each end. its electrons stop moving and point in the same direction. the net spins of many of its electrons are aligned. none of the above

the net spins of many of its electrons are aligned.

The force on an electron moving in a magnetic field will be least when its direction is the same as the magnetic field direction. perpendicular to the magnetic field direction. either of these neither of these

the same as the magnetic field direction.