Electric Charges and Fields Practice Questions
Class 12 · Physics · 1994 free MCQs with instant results and detailed explanations.
1994
Total
687
Easy
947
Medium
360
Hard
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Topics in Electric Charges and Fields
Electric Field
536
Electric Flux
444
Gauss's Law
507
Coulomb's Law
507
Sample Questions from Electric Charges and Fields
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What happens to the electrostatic force between two charges if the distance between them is doubled?
A.
The force is halved.
B.
The force is doubled.
C.
The force is quadrupled.
D.
The force is reduced to one-fourth.
Show Answer & Explanation
Correct Answer: D
According to Coulomb's Law, the electrostatic force is inversely proportional to the square of the distance between two charges. If the distance is doubled, the force becomes one-fourth of its original value.
Q2
Easy
If the charges are doubled but the distance remains the same, how does the electrostatic force change according to Coulomb's Law?
A.
The force remains the same.
B.
The force is doubled.
C.
The force is halved.
D.
The force is quadrupled.
Show Answer & Explanation
Correct Answer: B
Coulomb's Law states that force is directly proportional to the product of the charges. If both charges are doubled, the force also doubles.
Q3
Easy
What is the SI unit of electric charge?
A.
Coulomb
B.
Volt
C.
Ampere
D.
Ohm
Show Answer & Explanation
Correct Answer: A
The SI unit of electric charge is the Coulomb.
Q4
Medium
Two point charges, +3 ฮผC and -6 ฮผC, are placed 0.5 m apart. What is the force acting on the positive charge due to the negative charge?
A.
108 N, attractive
B.
54 N, repulsive
C.
27 N, attractive
D.
81 N, attractive
Show Answer & Explanation
Correct Answer: A
The force can be calculated using Coulomb's law: F = k * |q1 * q2| / r^2. Here, k = 9 ร 10^9 N mยฒ/Cยฒ, q1 = 3 ร 10^-6 C, q2 = -6 ร 10^-6 C, and r = 0.5 m. This results in a force of 108 N, which is attractive.
Q5
Medium
If the distance between two charges is doubled, how does the electrostatic force between them change?
A.
It quadruples.
B.
It doubles.
C.
It halves.
D.
It becomes one-fourth.
Show Answer & Explanation
Correct Answer: D
According to Coulomb's law, the force is inversely proportional to the square of the distance between the charges. If the distance is doubled, the force becomes one-fourth.
Q6
Medium
Three charges, +1 ฮผC, +1 ฮผC, and -2 ฮผC, are arranged in a straight line with a distance of 1 m between each. What is the net force on the -2 ฮผC charge?
A.
0 N
B.
0.18 N towards +1 ฮผC
C.
0.36 N towards +1 ฮผC
D.
0.18 N away from +1 ฮผC
Show Answer & Explanation
Correct Answer: C
The forces due to both +1 ฮผC charges on -2 ฮผC cancel each other, leading to a net force of 0.36 N towards the center.
Q7
Medium
What is the direction of the electric field at a point between two equal and opposite charges?
A.
Towards the positive charge
B.
Towards the negative charge
C.
Perpendicular to the line joining the charges
D.
Radially outward
Show Answer & Explanation
Correct Answer: B
The electric field direction is defined as the direction of force on a positive test charge, which points towards the negative charge.
Q8
Hard
If two identical charges of +5ฮผC each are placed 1 meter apart, what is the electric field at the midpoint between the charges?
A.
0
B.
9 ร 10^5 N/C
C.
4.5 ร 10^5 N/C
D.
2.25 ร 10^5 N/C
Show Answer & Explanation
Correct Answer: B
At the midpoint, the fields due to both charges add up as they are in the same direction, resulting in a net field of 9 ร 10^5 N/C.
Q9
Hard
What is the resultant force acting on a charge of -2ฮผC placed at a distance of 0.3 m from a +4ฮผC charge, considering another -4ฮผC charge is at 0.5 m from the -2ฮผC charge?
A.
1.2 N
B.
0.8 N
C.
1.6 N
D.
0.4 N
Show Answer & Explanation
Correct Answer: D
Calculate the forces acting on -2ฮผC due to +4ฮผC and -4ฮผC separately and then combine them considering their directions.
Q10
Hard
For a system of three charges, +Q, -Q, and +Q, arranged in a straight line with equal distances, what can be said about the net electric field at the midpoint of the arrangement?
A.
It is zero.
B.
It is directed towards +Q.
C.
It is directed away from -Q.
D.
It varies with distance.
Show Answer & Explanation
Correct Answer: A
The electric fields due to the two +Q charges cancel out the field due to -Q at the midpoint.
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Electric Charges and Fields โ Class 12 Physics Practice Questions Online
This page contains 1994 practice MCQs for the chapter Electric Charges and Fields in Class 12 Physics. The questions are organized by difficulty โ 687 easy, 947 medium, 360 hard โ so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 4 topics, giving you comprehensive coverage of the entire chapter.