Webassign Chapter 6

An atom consists of what?

A small positive nucleus surrounded at a distance by electrons

In a drawing of magnetic field lines, the stronger the field is, the

closer together the field lines are.

A current-carrying wire is in a magnetic field with the direction of the current perpendicular to that of the field.

The wire tends to move perpendicular to the field

What is true about a positive electric charge?

It repels other positive charges.

Which particle is the easiest to remove from an atom?

electron

When a magnetized iron bar is strongly heated, its magnetic field does what?

becomes weaker

When does an object have a positive electric charge

it has a deficiency of electrons

A compass needle tends to do what?

line up parallel to a magnetic field

At different places on the earth's surface, the earth's magnetic field

may be different in both magnitude and direction.

Superconductivity occurs in certain substances under what circumstances?

only at very low temperatures

A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is what?

perpendicular to the field

A molecule that has lost an electron becomes a

positive ion (cation)

The volt is the unit of electric

potential difference.

A magnet attracts

some substances and repels others

Relative to the electric force between two protons, the gravitational force between them is what?

weaker