Electrostatics Summative Assessment

What happens if Jane rubs a piece of fur on a hard rubber rod, giving the rod a negative charge?

• The fur is left neutral.

• Electrons are added to the rod.

• The fur is also charged negatively.

• Protons are removed from the rod.

When two different materials touch each other directly, some of the electrons in one material is transferred into the other material, this effect can be increased by rubbing the two surfaces together. What charging process is involved?

• conduction

• earthing

• friction

• induction

Which activity does not produce the same results as the other three?

• walking across a woolen carpet

• brushing dry hair with a plastic comb

• sliding over a plastic-covers automobile seat

• scraping food from a metal bowl with a metal spoon

Which of the following describes on the two objects that are charge by rubbing them together?

• Neither may be a conductor.

• They must be made of different materials.

• They will sometimes end up with both being positively charged.

• The heat produced by friction is a necessary part of this process.

If body X, with a positive charge, is used to charge body Y by induction, what will be the nature of the charge left on the latter?

• must be positive

• must be negative

• must be equal in magnitude to that on X

• must be greater in magnitude than that on X

You wish to use a positively charged rod to charge a ball by induction. Which statement is TRUE?

• The ball must be a conductor.

• The charge on the ball will be positive.

• The ball is charged as the area of contact between the two increases.

• The ball must be an insulator that is connected temporarily to the ground.

Rubber is a non-conducting material that is why it cannot easily conduct heat and electricity. Which is the best explanation for this kind of material?

• It has no electrons.

• It has few electrons.

• It has excess electrons which are loosely bounded with its nuclei so it can free to move.

• It has deficiency in electrons which are tightly bounded with its nuclei so it cannot move freely.

How can a charged object attract an uncharged object made of non-conducting material?

• Attraction of an insulator is not possible.

• The uncharged object must somehow gain a like charge.

• The charges in the uncharged object can become polarized.

• The uncharged object must somehow gain an unlike charge.

When you rub a plastic rod against your skin, electrons will likely move ____________________.

• from the rod to your skin

• from your skin to the rod

• simultaneously to your skin and the rod

• cannot be determined

An uncharged conductor is supported by an insulating stand. I pass a positively charged rod near the left end of the conductor, but do not touch it. The right end of the conductor will be __________.

• positive

• neutral

• negative

• attracted