Chapter 36 physics questions

switching of magnetic north to south and vice versa, the magnetism in earth's strata

What are magnetic pole reversals, and what evidence is there that the earth's magnetic field has undergone pole reversals throughout its history?

they can attract and repel without touching

What do electric charges have in common with magnetic poles?

a cluster of aligned atoms

What is a magnetic domain

The space around a magnet, in which a magnetic force is exerted. Its source is electric currents

What is a magnetic field, and what is its source?

charges can be isolated and poles cannot

What is a major difference between electric charges and magnetic poles?

difference between geographic and magnetic north

What is meant by magnetic declination?

fields of iron electrons don't entirely cancel

What is so special about iron that makes each iron atom a tiny magnet

concentric circles

What is the shape of the magnetic field that surrounds a current-carrying wire?

moving across magnetic field lines

What must a charged particle be doing in order to experience a magnetic force?

deflects a lot of charged particles from outer space

What role does the earth's magnetic field play in cosmic ray bombardment?

domains in some are aligned

Why do some pieces of iron behave as magnets, while other pieces of iron do not?

so it rotates more than 180 degrees

Why is it important that the current in the armature of a motor that uses a permanent magnet periodically change direction?

it jostles the domains out of alignment

Why will dropping or heating a magnet weaken it?

magnetic is perpendicular to field, electric is parallel

With respect to an electric and a magnetic field, how does the direction of a magnetic force on a charged particle differ from the direction of the electric force?

A piece of iron can be induced into becoming a magnet by simply placing it in a strong magnetic field. If you place a paperclip near a magnet, it itself will become a magnet because the domains become aligned in the magnetic field.

How can a piece of iron be induced into becoming a magnet? For example, if you place a paper clip near a magnet, it will itself become a magnet. Why?

force acts on the current in the field and deflect the galvanometer coil

How do the concepts of force, field, and current relate to a galvanometer?

forced the same way

How does the direction in which is a current-carrying wire is forced when in a magnetic field compare with the direction that moving charges are forced?

fields inside loop overlap

If a current-carrying wire is bent into a loop, why is the magnetic field stronger inside the loop than outside?

current inside the earth

According to most geophysics, what is the probable cause of the earth's magnetic field?

electrons spin in opposite direction so their fields cancel

Every spinning electron is a tiny magnet. Since all atoms have spinning electrons, why are not all atoms tiny magnets?