Electrostatics

A neutral metal sphere is touched by a negatively charged metal rod. As a result, the sphere will be _ and the metal rod will be _. Select the two answers in their respective order.

• positively charged

• negatively charged

• neutral

• much more massive

• not enough information to tell

A physics teacher rubs a glass object and a felt cloth together and the glass becomes positively charged. Which of the following statements are true?

• The glass gained protons during the rubbing process.

• The felt became charged negatively during this rubbing process.

• If the glass acquired a charge of +5 units, then the felt acquires a charge of -5 units.

• This event violates the law of conservation of charge.

• Electrons are transferred from glass to felt; protons are transferred from felt to glass.

A neutral metal sphere is touched by a negatively charged metal rod. During the process, electrons are transferred from the _ to the _ and the sphere acquires a _ charge.

• neutral sphere, charged rod, negative

• neutral sphere, charged rod, positive

• charged rod, neutral sphere, negative

• charged rod, neutral sphere, positive

A neutral metal sphere is touched by a positively charged metal rod. During the process, electrons are transferred from the _ to the _ and the sphere acquires a _ charge.

• charged rod, neutral sphere, negative

• charged rod, neutral sphere, positive

• neutral sphere, charged rod, negative

• neutral sphere, charged rod, positive

Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur?

• The rubber that the rod is made of is a better insulator than fur.

• The fur is a better insulator than the rubber.

• Molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur.

• Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod.

Two neutral conducting pop cans are touching each other. A positively charged balloon is brought near one of the cans as shown below. The cans are separated while the balloon is nearby, as shown. After the balloon is removed the cans are brought back together. When touching again, can X is _.

• positively charged

• negatively charged

• neutral

• impossible to tell

Two neutral conducting pop cans are touching each other. A negatively charged balloon is brought near Can X as shown below. As the balloon approaches Can X, there is a movement of electrons between the balloon and can X (in one direction or the other).

• True

• False

A positively charged balloon is brought near a neutral conducting sphere. While the balloon is near, the sphere is touched (grounded). At this point, there is a movement of electrons. Electrons move _ .

• into the sphere from the ground (hand)

• out of the sphere into the ground (hand)

• into the sphere from the balloon

• out of the sphere into the balloon

• from the ground through the sphere to the balloon

If a particle gained 1.2 x10^7 electrons, what is the charge on the particle?

If a particle has a charge of +4.5μC. How many electrons has it lost?