Charge

A neutral plastic rod is rubbed by a piece of animal fur.  Describe the charge on each item.

• Both items will be neutral.

• The fur and the rod will both have a negative net charge.

• The rod will have a negative net charge and the fur will have a positive net charge.

• The rod will have a positive net charge and the fur will have a negative net charge.

A positively charged object is moved towards a negatively charged object.  What is the motion of the objects when they come close to each other?

• Neither object has any effect on the other.

• The objects move away from each other.

• The objects move towards each other.

A neutral glass rod is rubbed by a piece of silk with no net charge.  The rod gains a positive net charge and the silk gains a net negative charge.  What is the sum of the charges on the silk and the rod?

• Zero

• Twice the charge on the rod.

• Twice the charge on the silk.

• One half of the charge on the rod.

An atom in its normal (non-ionic) state has no charge.  This is due to the fact that atoms:

• have only neutrons.

• have no protons or electrons.

• have equal numbers of protons and electrons.

•    have an equal number of protons and neutrons.

An atom is composed of:

• a central nucleus that is surrounded by neutrons.

• an even distribution of electrons and protons in a spherical shape.

• a central nucleus surrounded by electrons.

•    a central nucleus containing protons and electrons.

Free electrons in a conductor will:

• move freely in random directions throughout the entire volume of the conductor.

• be located at the center of the conductor.

• have no organized distribution.

•    only move short distances.

Compared to insulators, metals are better conductors of electricity because metals contain more free _____.

• positive ions.

• negative ions.

• protons.

• electrons.

Electrons in an insulator are:

• bound to their atoms, but may move freely throughout the solid.

• not bound to their atoms and may move freely throughout the solid.

• bound to their atoms and may not move at all within the solid.

• bound to their atoms, but may move short distances within their solid.