3rd Quarter exam. Grade 12.

A plastic rod is rubbed with a piece of animal fur. The plastic rod acquires a negative charge during this process. Which of the following is true about the charge on the piece of fur?

• It acquires a positive charge but greater in magnitude than the rod

• It acquires a positive charge but less in magnitude than the rod

• It acquires a negative charge but greater in magnitude than the rod

• It acquires a positive charge with the same magnitude as the rod

A positively charged rod is brought close to one end of a neutral metallic plate. What type of charge is induced on the closest side of the plate?

• Positive

• Negative

• Neutral

• It depends of the separation between the rod and plate

A positively charged rod is brought close to one end of a neutral metallic plate. What type of charge is induced on the farthest side of the plate?

• Positive

• Negative

• Neutral

• It depends of the separation between the rod and plate

Two positive charges with magnitudes 4Q and Q are separated by a distance r. Which of the following statements is true?

• The charge with a greater magnitude exerts a larger force on the small charge

• The charge with a greater magnitude exerts a smaller force on the small charge

• The forces on each charge are the same in magnitude and opposite in direction

• The forces on each charge are the same in magnitude and pointing in the same direction

Sphere A is charged positively and sphere B is neutral. The spheres are brought near each other. Which of the following statements is true?

• There is no electrostatic force between the spheres since one is neutral

• There is a repulsive electrostatic force between the spheres

• There is an attractive electrostatic force between the spheres

• There is a repulsive electrostatic force applied only on sphere B

Two positive charges Q1 and Q2 are separated by a distance r. The charges repel each other with a force F. If the magnitude of each charge is doubled and the distance stays unchanged what is the new force between the charges?

• F

• 2 F

• 4 F

• 1/4 F

Two positive charges Q1 and Q2 are separated by a distance r. The charges repel each other with a force F. If the distance between the charges is cut to one-fourth what is the new force acting on each charge?

• 16 F

• 2 F

• 4 F

• 1/4 F

Sphere A carries a positve charge 4Q and sphere B is neutral.

Initially the spheres are separated by a distance r. The spheres

briefly touch each other and move to the initial separation. What

is the new charge on each sphere?

• Q

• 4Q

• 1/4Q

• 1/2Q

A positively charged sphere with a charge of +8Q is separated

from a negatively charged sphere -2Q by a distance r. The

spheres briefly touch each other and move to the original

distance r. What is the new charge on each sphere after they

move to the distance r?

• Q

• 2Q

• 3Q

• 1/2 Q

A positively charged sphere with a charge of +8Q is separated

from a negatively charged sphere -2Q by a distance r. There is

an attractive force F exerted on each sphere. The spheres

briefly touch each other and move to the original distance r.

What is the new force on each sphere in terms of F?

• 9/16 F

• 16/9 F

• 9/4 F

• 4/9 F