Electrostatic Forces

What do you call the process of charging a conductor by bringing it near another charged object?

• induction

• polarization

• neutralization

• conduction

A negatively charged plastic comb is brought close to, but does not touch, a small piece of paper. If the comb and the paper are attracted to each other, the charge on the paper

• must be positive

• must be negative

• may be neutral or negative

• may be neutral or positive

A positively charged rod is held near the knob of a neutral electroscope. What best describes what will happen to the leaves?

• The electrons attract to the top and the leaves will be positive and spread

• The electrons attract to the top and the leaves will be positive and and stay closed

• The electrons repel to the bottom and the leaves will be negative and spread

• The electrons repel to the bottom and the leaves will be negative and stay closed

Two electrically neutral metal spheres, A and B, on insulating stands are placed in contact with each other. A negatively charged rod is brought NEAR, but does not touch the spheres, as shown in the diagram below. How are the spheres now charged?

• A is positive and B is positive.

• A is negative and B is positive.

• A is positive and B is negative.

• A is negative and B is negative.

Three charged metal spheres, X, Y, and Z, are on insulating stands. All three spheres are simultaneously brought into contact with each other in the process of CONDUCTION and then returned to their original positions.

Which statement best describes the charge of the spheres after this procedure is completed?

• All the spheres will end up with the same charge

• All the spheres are neutral

• Sphere Y has a greater charge than spheres X or Z

• Each sphere retains the same charge that it had originally

Electrostatic force F exists between two point charges. If the BOTH charges are DOUBLED, the force between the charges will be...

HINT: Electric Force is DIRECTLY RELATED in the same way to the amount of charge (times 2 of them)

• F

• 4F

• 2F

• F/4

What will happen to the electrostatic Force if the distance is 1/2 of before?

HINT: Electric Force is INVERSELY RELATED TO THE SQUARE of the distance (so opposite and squared)

• it will be 2F

• it will be 4F

• it will be 1/2 F

• it will be 1/4 F

Metal sphere A has a charge of -2 units and an identical metal sphere, B, has a charge of -4 units. If the spheres are brought into contact with each other and then separated, the spheres will share charge equally and B will _____

• gain 1 electron

• lose 1 electron

• gain 3 electrons

• lose 3 electrons

A NEGATIVELY charged rod TOCHES the knob of a neutral electroscope. Which best represents the distribution of charge on the electroscope.

• both the knob and leaves become positive

• both the knob and leaves become negative

• the knob becomes negative and the leaves become positive

• the knob becomes positive and the leaves become negative

Electrostatic force F exists between two point charges. If the ONE charge is tripled (x3) AND the distance are tripled (x3), the force between the charges will be...

HINT: Electric Force is DIRECTLY RELATED to charge and INVERSELY RELATED TO THE SQUARE of the distance

• 3 x 3 = 9F

• 3 x 1/3 = 1F

• 3 x 9 = 27F

• 3 x 1/9 = 1/3F