MagnetismReview

For magnets, like poles repel each other and unlike poles

a. also repel each other.b. attract each other.c. can disappear into nothingness.d. can carry a lot of energy.

For magnets, like poles repel each other and unlike poles

a. also repel each other.b. attract each other.c. can disappear into nothingness.d. can carry a lot of energy.

The source of all magnetism is

a. tiny bits of iron.b. tiny domains of aligned atoms.c. the motion of electrons.d. small lodestones.

The source of all magnetism is

a. tiny bits of iron.b. tiny domains of aligned atoms.c. the motion of electrons.d. small lodestones.

Comment: This is true for electrons moving in a beam or electrons spinning or orbiting the nuclei of atoms such as iron.

A strong magnet lifts a paper clip. Compared with the force the magnet exerts on the clip, the force the clip

exerts on the magnet isa. much less.b. slightly less.c. the same.d. slightly more.

A strong magnet lifts a paper clip. Compared with the force the magnet exerts on the clip, the force the clip

exerts on the magnet isa. much less.b. slightly less.c. the same.d. slightly more.

Explanation: This is Newton’s third law. In the interaction between the paper clip and the magnet, both forces are equal and opposite.

Magnet A has twice the field strength of Magnet B. When brought close

together, the magnet that pulls harder on the other is

a. Magnet A.b. Magnet B.c. Both forces are equally strong.d. dependent on their distances apart.

Magnet A has twice the field strength of Magnet B. When brought close

together, the magnet that pulls harder on the other is

a. Magnet A.b. Magnet B.c. Both forces are equally strong.d. dependent on their distances apart.

Explanation: This is Newton’s third law–the force that A exerts on B is equal and opposite to the force that B exerts on A.

Surrounding moving electric charges are

a. electric fields.b. magnetic fields.c. Both of these.d. None of these.

Surrounding moving electric charges are

a. electric fields.b. magnetic fields.c. Both of these.d. None of these.

Comment: Don’t forget that electric fields surround electric charges!

The magnetic domains in a magnet produce a weaker magnet when the

magnet is

a. heated.b. dropped on a hard surface.c. Either of these.d. None of these.

The magnetic domains in a magnet produce a weaker magnet when the

magnet is

a. heated.b. dropped on a hard surface.c. Either of these.d. None of these.

Magnetic domains occur mainly for materials composed of

a. carbon.b. copper.c. silver.d. iron.

Magnetic domains occur mainly for materials composed of

a. carbon.b. copper.c. silver.d. iron.

A bar magnet that holds a chain of paper clips illustrates

a. magnetic field displacement.b. magnetic induction.c. electromagnetic induction.d. Faraday’s law.

A bar magnet that holds a chain of paper clips illustrates

a. magnetic field displacement.b. magnetic induction.c. electromagnetic induction.d. Faraday’s law.

When a bar magnet is broken in half, the magnetic strength of each piece is

a. less than half.b. about half.c. the same.d. somewhat increased.

When a bar magnet is broken in half, the magnetic strength of each piece is

a. less than half.b. about half.c. the same.d. somewhat increased.

The magnetic field lines about a current-carrying wire form

a. circles.b. radial lines.c. eddy currents.d. spirals.

The magnetic field lines about a current-carrying wire form

a. circles.b. radial lines.c. eddy currents.d. spirals.

A magnetic force cannot act on an electron when it

a. is at rest.b. moves parallel to magnetic field lines.c. Both of these.d. None of these.

A magnetic force cannot act on an electron when it

a. is at rest.b. moves parallel to magnetic field lines.c. Both of these.d. None of these.

Explanation: A force is exerted on charged particles only when they move at an angle to magnetic field lines. The force is greatest when motion is at right angles to the magnetic field.

A magnetic force acts most strongly on a current-carrying wire when it

a. carries a very large current.b. is perpendicular to the magnetic field.c. Either or both of these.d. None of the above.

A magnetic force acts most strongly on a current-carrying wire when it

a. carries a very large current.b. is perpendicular to the magnetic field.c. Either or both of these.d. None of the above.

The magnetic field surrounding Earth

a. helps shield us from cosmic rays.b. is likely caused by electric currents in its

interior.c. changes over time.d. All of these.

The magnetic field surrounding Earth

a. helps shield us from cosmic rays.b. is likely caused by electric currents in its

interior.c. changes over time.d. All of these.

Magnetic materials are found in the bodies of

a. bees.b. birds.c. bacteria.d. All of these.

Magnetic materials are found in the bodies of

a. bees.b. birds.c. bacteria.d. All of these.