Sample Electric Field Questions
1) The electric force acting on a test charge (q) at a point divided by the value of the charge is the:
a) acceleration of the charge.
b) electric field created by the test charge.
c) electric field acting on the test charge.
d) the energy of the test charge.
2) The electric field at a distance of 2 mm from a test charge is ___ the field at a distance of 4 mm.
a) the same as
b) twice as strong as
c) four times as strong as
d) half as strong as
e) one fourth as strong as
3) The electric field midway between two equal positive charges
a) is twice as strong as the field of one charge alone.
b) is half as strong as the field of one charge alone.
c) is zero
4) The electric field midway between equal positive and negative charges
a) is twice as strong as the field of one charge alone and points toward the negative charge.
b) is twice as strong as the field of one charge alone and points toward the positive charge.
c) is zero
5) Which of the following is not true about electric field lines?
a) Lines begin on positive charge and end on negative.
b) Lines are close together where the field is strong.
c) The direction of the electric force on a charge is tangent to the field line.
d) All these statements are true.
e) None of these statements are true.
6) Electric field lines
a) Never cross.
b) Cross midway between two equal charges.
c) Are always straight lines.
7) If a negative charge is moving to the north in an electric field which is directed to the north, the charge
will:
a) speed up
b) slow down
c) be unaffected
8) In the figure below Q1 is negative and Q2 is positive. The direction of the resultant field at the point
shown is approximately:
a) a
b) b
c) c
d) d
e) e
f)
f
g) g
h) h
Ans: 1-c, 2-e, 3-c, 4-a, 5-d, 6-a, 7-b, 8-h
Draw the electric field produce by the following: Indicate where E = 0. For every unit of charge use 2 field lines.
+2
+2
-4
+2
What information can be concluded about the following?
9.
Other than at infinity, the electric field strength is zero at a point on the line in which of the following ranges?
(A) To the left of I
(B) Between I and II
(C) Between II and III
(D) To the right of III
(E) None; the field is zero only at infinity.
10. If the only force acting on an electron is due to a uniform electric field, the electron moves with constant
(A) acceleration in a direction opposite to that of the field
(B) acceleration in the direction of the field
(C) acceleration in a direction perpendicular to that of the field
(D) speed in a direction opposite to that of the field
(E) speed in the direction of the field
11. A positive charge of 3.0 x 10-8 coulomb is placed in an upward directed uniform electric field of 4.0 x 10 4 N/C. When the charge
is moved 0.5 meter upward, the work done by the electric force on the charge is
(A) 6 x 10-4 J
(B) 12 x 10-4 J
(C) 2 x 104 J (D) 8 x 104 J
(E) 12 x 104 J
Questions 12-13 relate to the following configurations of electric charges located at the vertices of an equilateral triangle. Point P is
equidistant from the charges.
12. In which configuration is the electric field at P equal to zero?
(A)
(B)
(C)
(D)
(E)
13. In which configuration is the electric field at P pointed at the midpoint between two of the charges?
(A)
(B)
(C)
(D)
(E)