Deck 8: Electric Potential and Gauss Law

Question 1

If 500 J of work are required to carry a 40-C charge from one point to another, the potential difference between these two points is:

A) 12.5 V
B) 20,000 V
C) 0.08 V
D) depends on the path
E) none of these

Answer 1

12.5 V

Question 2

The potential difference between two points is 100 V. If a particle with a charge of 2 C is transported from one of these points to the other, the magnitude of the work done is:

A) 200 J
B) 100 J
C) 50 J
D) 100 V
E) 2 J

Answer 2

200 J

Question 3

Positive charge is distributed uniformly throughout a non-conducting sphere. The highest electric potential occurs:

A) at the center
B) at the surface
C) halfway between the center and surface
D) just outside the surface
E) far from the sphere

Answer 3

at the center

Question 4

Eight identical spherical raindrops are each at a potential V, relative to the potential far away. They coalesce to make one spherical raindrop whose potential is:

A) V/8
B) V/2
C) 2V
D) 4V
E) 8V

Question 5

Equipotential surfaces associated with an electric dipole are:

A) spheres centered on the dipole
B) cylinders with axes along the dipole moment
C) planes perpendicular to the dipole moment
D) planes parallel to the dipole moment
E) none of the above

Question 6

The potential difference between its ends of a 2-meter stick that is parallel to a uniform electric field is 400 V.The magnitude of the electric field is:

A) zero
B) 100 V/m
C) 200 V/m
D) 400 V/m
E) 800 V/m

Question 7

A conducting sphere has charge Q and its electric potential is V, relative to the potential far away. If the charge is doubled to 2Q, the potential is:

A) V
B) 2V
C) 4V
D) V/2
E) V/4

Question 8

Consider Gauss law: Which of the following is true?

A) must be the electric field due to the enclosed charge
B) If q = 0 then everywhere on the Gaussian surface
C) If the three particles inside have charges of +q, +q and-2q, then the integral is zero
D) On the surface is everywhere parallel to
E) If a charge is placed outside the surface, then it cannot affect on the at any point on the surface

Question 9

10 C of charge are placed on a spherical conducting shell. A particle with a charge of -3-C point charge is placed at the center of the cavity. The net charge in coulombs on the inner surface of the shell is:

A) -7
B) -3
C) 0
D) +3
E) +7

Question 10

10 C of charge are placed on a spherical conducting shell. A particle with a charge of -3C is placed at the center of the cavity. The net charge in coulombs on the outer surface of the shell is:

A) -7
B) -3
C) 0
D) +3
E) +7

Question 11

Charge is distributed uniformly along a long straight wire. The electric field 2 cm from the wire is 20 N/C. The electric field 4 cm from the wire is:

A) 120 N/C
B) 80 N/C
C) 40 N/C
D) 10 N/C
E) 5 N/C

Question 12

A long line of charge with charge per unit length runs along the cylindrical axis of a cylindrical shell which carries a charge per unit length of $\lambda$ _c.The charge per unit length on the inner and outer surfaces of the shell, respectively are:

A) and $\lambda$ _c
B) and $\lambda$ _c +
C) and $\lambda$ _c - $\lambda$ _c
D) + $\lambda$ _c and $\lambda$ _c -
E) - $\lambda$ _c and $\lambda$ _c +

Question 13

Charge is distributed uniformly on the surface of a large flat plate. The electric field 2 cm from the plate is 30 N/C. The electric field 4 cm from the plate is:

A) 120 N/C
B) 80 N/C
C) 30 N/C
D) 15 N/C
E) 7.5 N/C