1. What is the electric potential at a point due to a positive point charge?
A.
Positive
B.
Negative
C.
Always zero
D.
Undefined at every point
Correct Answer:
Positive
Explanation:
Taking potential at infinity as zero, the potential due to a positive charge is V = kq/r, which is positive.
2. What is the electric potential at a point due to a negative point charge?
A.
Positive
B.
Negative
C.
Always zero
D.
Always equal to the electric field
Correct Answer:
Negative
Explanation:
For a negative charge, q is negative in V = kq/r, so the electric potential is negative when infinity is taken as zero potential.
3. The electric potential due to several charges is found by:
A.
Adding their potentials algebraically
B.
Adding only the magnitudes of their potentials
C.
Multiplying their potentials
D.
Adding their electric field magnitudes
Correct Answer:
Adding their potentials algebraically
Explanation:
Electric potential is a scalar, so the potential contributions are added algebraically, including their positive or negative signs.
4. A point is equidistant from a +q charge and a -q charge. What is the net electric potential at that point?
A.
Positive
B.
Negative
C.
Zero
D.
Infinite
Correct Answer:
Zero
Explanation:
The two charges produce equal-magnitude potentials with opposite signs at equal distances, so their algebraic sum is zero.
5. If the potential at a point due to one charge is +5 V and due to another charge is -2 V, what is the total potential?
A.
+7 V
B.
+3 V
C.
-3 V
D.
-7 V
Correct Answer:
+3 V
Explanation:
Potentials are added algebraically: (+5 V) + (-2 V) = +3 V.
6. If the potential at a point due to one charge is -6 V and due to another charge is -4 V, what is the total potential?
A.
+10 V
B.
+2 V
C.
-2 V
D.
-10 V
Correct Answer:
-10 V
Explanation:
Both potential contributions are negative, so their algebraic sum is (-6 V) + (-4 V) = -10 V.
7. With zero potential chosen at infinity, what is the potential at a point infinitely far from an isolated charge?
A.
Positive infinity
B.
Negative infinity
C.
Zero
D.
One volt
Correct Answer:
Zero
Explanation:
By convention, the electric potential at infinity is taken as zero for an isolated charge.
8. A positive charge and a negative charge produce potentials of +8 V and -8 V at a point. What is the net potential there?
A.
+16 V
B.
-16 V
C.
0 V
D.
+8 V
Correct Answer:
0 V
Explanation:
The equal and opposite potential contributions cancel algebraically: (+8 V) + (-8 V) = 0 V.
9. At a point, the potential due to a positive charge is +4 V and that due to a negative charge is -7 V. What is the net potential?
A.
+11 V
B.
+3 V
C.
-3 V
D.
-11 V
Correct Answer:
-3 V
Explanation:
Adding the signed potentials gives (+4 V) + (-7 V) = -3 V, so the net potential is negative.
10. If all charge contributions at a point give negative electric potentials, the net electric potential at that point is:
A.
Positive
B.
Negative
C.
Always zero
D.
Independent of the signs of the charges
Correct Answer:
Negative
Explanation:
When every contribution is negative, their algebraic sum remains negative, so the net electric potential is negative.
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