PY212 Midterm 1

Which of the following statements are true for electric field lines? 1) Electric field lines can never intersect. 2) Electric field lines are continuous; they do not have a beginning or an ending. 3) Electric field lines point away from positive charges and toward negative charges. 4) Electric field lines are close together in regions of space where the magnitude the electric field is weak and are father apart where it is strong. 5) At every point in space, the electric field vector at that point is tangent to the electric field line through that point.

1) Electric field lines can never intersect. 3) Electric field lines point away from positive charges and toward negative charges. 5) At every point in space, the electric field vector at that point is tangent to the electric field line through that point.

Which are true? 1) In a uniform electric field, the field lines are straight, parallel, and uniformly spaced. 2) Electric field lines near positive point charges radiate outward. 3) The electric force acting on a point charge is proportional to the magnitude of the point charge. 4) Electric field lines near negative point charges circle clockwise. 5) The electric field created by a point charge is constant throughout space.

1) In a uniform electric field, the field lines are straight, parallel, and uniformly spaced. 2) Electric field lines near positive point charges radiate outward. 3) The electric force acting on a point charge is proportional to the magnitude of the point charge.

Which are true: 1) Two negative charges repel each other. 2) A neutral object contains no charge carriers. 3) Electric charge is quantized. 4) Electric charge is conserved. 5) Two positive charges attract each other. 6) A positive charge and a negative charge attract each other.

1) Two negative charges repel each other. 3) Electric charge is quantized. 4) Electric charge is conserved. 6) A positive charge and a negative charge attract each other.

Which of the following statements are true? 1) When all charges are at rest, the surface of a conductor is always an equipotential surface. 2) The potential energy of a test charge increases as it moves along an equipotential surface. 3) Electric field lines and equipotential surfaces are always mutually perpendicular. 4) The potential energy of a test charge decreases as it moves along an equipotential surface. 5) An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point.

1) When all charges are at rest, the surface of a conductor is always an equipotential surface. 3) Electric field lines and equipotential surfaces are always mutually perpendicular. 5) An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point.

A disk with a radius of R is oriented with its normal unit vector at an angle θ with respect to a uniform electric field. Which of the following would result in an increase in the electric flux through the disk? 1) increasing the strength of the electric field 2) increasing the given orientation angle of the disk, but not exceeding an angle of 90° 3) decreasing the area of the disk 4) increasing the area of the disk 5) decreasing the strength of the electric field 6) decreasing the given orientation angle of the disk

1) increasing the strength of the electric field 4) increasing the area of the disk 6) decreasing the given orientation angle of the disk

The strength of the electric field at a certain distance from a point charge is represented by E. What is the strength of the electric field at twice the distance from the point charge? At twice the distance, the strength of the field is E/2. At twice the distance, the strength of the field remains equal to E. At twice the distance, the strength of the field is 4E. At twice the distance, the strength of the field is 2E. At twice the distance, the strength of the field is E/4.

At twice the distance, the strength of the field is E/4.

A net charge is placed on a hollow conducting sphere. How does the net charge distribute itself? The net charge uniformly distributes itself throughout the thickness of the conducting sphere. The net charge uniformly distributes itself on the sphere's inner and outer surfaces. The net charge uniformly distributes itself on the sphere's outer surface. The net charge clumps together at some location within the sphere. The net charge uniformly distributes itself on the sphere's inner surface.

The net charge uniformly distributes itself on the sphere's outer surface.

Is it possible for the electric field between two positive charges to equal zero along the line joining the two charges? Yes, regardless of the magnitude of the two charges. No, a zero electric field cannot exist between the two charges. This cannot be determined without knowing the separation between the two charges. Yes, but only if the two charges are equal in magnitude.

Yes, regardless of the magnitude of the two charges.

Suppose you have two point charges of opposite sign. As you move them farther and farther apart, the potential energy of this system relative to infinity: stays the same. increases. decreases.

increases