Module 4: Electrical Potential

Question 1

When a positive charge moves opposite to the direction of the electric field,

a) the field does negative work on it and the potential energy increases.
b) the field does positive work on it and the potential energy decreases.
c) the field does negative work on it and the potential energy decreases.
d) the field does positive work on it and the potential energy increases.

Answer 1

a) the field does negative work on it and the potential energy increases.

Question 2

If the three-point charges shown here lie at the vertices of an equilateral triangle, the electric potential at the center of the triangle is

a) not enough information
b) zero
c) negative
d) positive

Answer 2

c) negative

Question 3

If the electric field is zero everywhere inside a region of space, the potential must also be zero in that region.

Answer 3

False

Question 4

When a positive charge moves in the direction of the electric field,

a) the field does negative work on it and the potential energy increases.
b) the field does negative work on it and the potential energy decreases.
c) the field does positive work on it and the potential energy increases.
d) the field does positive work on it and the potential energy decreases.

Answer 4

d) the field does positive work on it and the potential energy decreases.

Question 5

When a negative charge moves in the direction of the electric field,

a) the field does negative work on it and the potential energy increases.
b) the field does positive work on it and the potential energy decreases
c) the field does negative work on it and the potential energy decreases
d) the field does positive work on it and the potential energy increases

Answer 5

a) the field does negative work on it and the potential energy increases.

Question 6

If the three-point charges shown here lie at the vertices of an equilateral triangle, the electric potential at the center of the triangle is

a) negative
b) zero
c) not enough information
d) positive

Answer 6

d) positive

Question 7

Consider a point P in space where the electric potential is zero. Which statement is correct?

a) not enough information given to decide
b) The electric field at points around P is directed toward P.
c) A point charge placed at P would feel no electric force
d) The electric field at points around P is directed away from P.

Answer 7

a) not enough information given to decide

Question 8

Where an electric field line crosses an equipotential surface, the angle between the field line and the equipotential is

a) zero.
b) between zero and 90°
c) not enough information given to decide
d) 90°

Answer 8

d) 90°

Question 9

Suppose a region of space has a uniform electric field, directed toward the right, as shown in the figure. Which statement is true?

a) The voltage at points A and B are equal, and the voltage at point C is lower than the voltage at point A.
b) The voltage at point A is the highest, the voltage at point B is the second highest, and the voltage at point C is the lowest.
c) The voltage at all three locations is the same.
d) The voltage at points A and B are equal, and the voltage at point C is higher than the voltage at point A.
e) None of the above

Answer 9

a) The voltage at points A and B are equal, and the voltage at point C is lower than the voltage at point A.

Question 10

Three charges form an equilateral triangle with 1.6 cm long sides. What is the electric potential at the point indicated with the dot?

a) + V
b) - V
c) zero

Answer 10

c) zero

Question 11

If the electrical potential in a region is constant, the electric field must be zero everywhere in that region.

Answer 11

True