General Physics 2( 2nd Summative)

To which of the following is an electric field most directly related?

• the momentum of a test charge

• the kinetic energy of a test charge

• the force acting on a test charge

• the potential energy of a test charge

Which of the following statements concerning electric field lines is correct?

• Field lines may cross.

• Field lines are close together where the field is large.

• Field lines point away from a negatively charged particle.

• A charged point particle released from rest moves along a field line.

Which of the following best defines electric flux?

• The rate at which charge flows through a surface.

• The total electric field passing through a given surface.

• The force experienced by a test charge in an electric field.

• The total electric field passing through a unit area perpendicular to the field.

The outer surface of the cardboard center of a paper towel roll:

• is a possible Gaussian surface

• cannot be a Gaussian surface since it is an insulator

• cannot be a Gaussian surface because it encloses no charge

• cannot be a Gaussian surface because it is not a closed surface

Which of the following statements is INCORRECT?

• Gauss’ law can be derived from Coulomb’s law.

• Coulomb’s law can be derived from Gauss’ law and symmetry.

• Gauss’ law applies to a closed surface of any shape.

• If no net charge is enclosed by a closed surface, the electric field on the surface itself is zero.

When you rub a plastic rod with fur, the plastic rod becomes negatively charged and the fur becomes positively charged. As a consequence of rubbing the rod with the fur,

• the rod and fur both gain mass.

• the rod and fur both lose mass.

• the rod gains mass and the fur loses mass.

• the rod loses mass and the fur gains mass.

A positively charged piece of plastic exerts an attractive force on an electrically neutral piece of paper. This is because

• electrons are less massive than atomic nuclei.

• a typical atom has many electrons but only one nucleus.

• an atomic nucleus occupies only a small part of the volume of an atom.

• the electric force between charged particles decreases with increasing distance.

What must be done to an initially uncharged object in order to give it a net negative charge?

• Introduce additional atoms to the object.

• Increase the number of electrons in the object.

• Remove a specific number of atoms from the object.

• Decrease the number of electrons in the object while keeping the protons constant.

An electron travelling horizontally from North to South enters a region where a uniform electric field is directed downward. What is the direction of the electric force exerted on the electron force once it has entered the field?

• Upward

• Downward

• To the East

• To the West

What is the electric field strength at a point 10 cm from a charge q = +2.0 nC?

• 0.180 N/C

• 180 N/C

• 1800 N/C

• 180,000 N/C