Magnetism

Because magnetic force on a moving electron is always perpendicular to its direction of motion, magnetic force cannot change an electron's: A:speed. B:direction. C:speed and direction. D:none of the above

A

Earth's magnetic field affects cosmic rays by: A:deflecting them. B:slowing their speeds. C:absorbing them. D:none of the above

A

Into which stable force field can a proton be placed at rest without being accelerated? A:Magnetic field. B:Electric field. C:both of these D:None of these

A

Magnetic domains

A group of atoms whose magnetic fields are aligned

Electromagnet

A magnet whose field is produced by an electric current

In what sense are all magnets electromagnets?

All magnets are electromagnets because all magnetism is from moving particles and it its charged its electric so electromagnet

A friend tells you that the metal aluminum is beneath a layer of white-painted plastic of your refrigerator door. How could you check without scraping if this is true?

Aluminum is not magnetic so it shouldn't stick

The direction of magnetic field lines about a current-carrying wire: A) extend radially from the wire. B) circle the wire in closed loops. C) both of these D) none of the above

B

When a current-carrying wire is bent into a loop, the magnetic field inside the loop: A: weakens. B: strengthens. C: cancels. D: none of the above

B

If a magnet produces a force on a current-carrying wire, the wire: A:is likely warmed. B:may produce a force on the magnet. C:produces a force on the magnet. D:none of these

C

Electricity and Magneticm

Closely related and caused by motion of electrons

An iron bar magnet is given a slight electric charge. Surrounding the charged bar is: A) a magnetic field. B) an electric field. C) a gravitational field. D) all of the above

D

The magnetic field strength inside a current-carrying coil is greater when the coil encloses A: a vacuum. B:a wooden rod. C:a glass rod. D:an iron rod.

D

If you place a chunk of iron near the north pole of a magnet, attraction will occur. Why will attraction also occur if you place the same iron near the south pole of the magnet?

Similarly south pole induces north poles in the irons causing attraction

Do the poles of a horseshoe magnet attract each other? If you bend the magnet so that the poles get closer together, what happens to the force between the poles?

The force increases. opposite magnetic poles attract each other

Magnetic field

The space around a magnet is a magnetic field. Also produced by the motion of electric charge.

All atoms have moving electric charges. Why, then, aren't all materials magnetic?

all materials are not metal and magnetic. equal numbers of electrons spin in opposite directions which cancels out magnetism

When a galvanometer is calibrated to read potential difference it becomes: A:an ammeter. B:a voltmeter. C:an ohm meter. D:none of the above

b

No magnetic force acts on a current carrying wire when it: A:carries a very small current. B:is perpendicular to the magnetic field. C:either or both of these D:none of the above

d

But there is a very important difference between magnetic poles and electric charges.

electric charges can be isolated, magnetic poles cannot.

What kind of force field surrounds a stationary electric charge? What additional field surrounds it when it moves?

if it is moving a magnetic field appears. A stationary charge will produce only and electric field in the area.

Biomagnetism

magnetic material located in living organisms

What is different about the magnetic poles of common refrigerator magnets and those of common bar magnets?

refrigerator magnets the north and south poles are alternatively located and adjacent to each other in strips. a common magnet has a north at one end and south at the other end.

Why aren't permanent magnets really permanent?

since it can be de-magnetized and re-magnetized, it is not really permanent.

magnetic force

the attraction or repulsion between magnetic poles