Q. If the electric field inside a conductor in electrostatic equilibrium is zero, what can be said about the electric field just outside the conductor?
A.
It is zero
B.
It is uniform
C.
It is perpendicular to the surface
D.
It is parallel to the surface
Solution
The electric field just outside a conductor in electrostatic equilibrium is perpendicular to the surface.
Correct Answer:
C
— It is perpendicular to the surface
Q. If the electric potential at a point is 10 V and the electric field is uniform, what is the work done in moving a charge of 2 C from that point to a point where the potential is 0 V?
A.
20 J
B.
10 J
C.
5 J
D.
0 J
Solution
Work done W = q(V1 - V2) = 2 C (10 V - 0 V) = 20 J.
Q. If the electric potential at a point is 150 V and the electric field is directed towards the point, what can be said about the charge creating the field?
A.
It is positive
B.
It is negative
C.
It is neutral
D.
Cannot be determined
Solution
If the electric field is directed towards the point, it indicates that the charge creating the field is negative.
Q. If the electric potential at a point is 200 V and the electric field is uniform, what is the work done in moving a charge of 0.5 C to a point where the potential is 100 V?
A.
50 J
B.
100 J
C.
200 J
D.
0 J
Solution
Work done W = q * (V1 - V2) = 0.5 C * (200 V - 100 V) = 50 J.
Q. If the electric potential at a point is 300 V and the electric field is uniform, what is the work done in moving a charge of 3 μC to a point where the potential is 600 V?
A.
0.9 mJ
B.
0.6 mJ
C.
0.3 mJ
D.
1.2 mJ
Solution
Work done W = q * ΔV = 3 × 10^-6 C * (600 V - 300 V) = 3 × 10^-6 * 300 = 0.9 mJ.
Q. If the electric potential at a point is 50 V and the electric field strength is 5 N/C, what is the distance from the point to the reference point where the potential is zero?
Q. If the electric potential at a point is increased, what happens to the electric field at that point?
A.
Increases
B.
Decreases
C.
Remains the same
D.
Cannot be determined
Solution
An increase in electric potential at a point generally indicates a stronger electric field, as the electric field is related to the rate of change of potential.
Q. If the electric potential at point A is 5 V and at point B is 15 V, what is the work done by the electric field in moving a charge of 2 C from A to B?
A.
-20 J
B.
20 J
C.
10 J
D.
30 J
Solution
Work done W = Q(V_B - V_A) = 2 C * (15 V - 5 V) = 20 J.
Q. If the radius of a spherical Gaussian surface is doubled while keeping the charge inside constant, how does the electric field change?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Solution
The electric field E due to a point charge decreases with the square of the distance from the charge, so if the radius is doubled, the electric field halves.
Q. If the radius of a spherical Gaussian surface is doubled, how does the electric field change if the enclosed charge remains constant?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Solution
The electric field E due to a point charge decreases with the square of the distance from the charge, so if the radius is doubled, the electric field halves.
Electrostatics is a crucial topic in physics that deals with the study of electric charges at rest. Understanding electrostatics is essential for students preparing for school exams and competitive tests, as it forms the foundation for many advanced concepts in physics. Practicing MCQs and objective questions on electrostatics not only enhances conceptual clarity but also boosts your confidence in tackling important questions during exams.
What You Will Practise Here
Fundamental concepts of electric charge and its properties
Understanding Coulomb's Law and its applications
Electric field and electric potential: definitions and calculations
Capacitance and capacitors: types and formulas
Gauss's Law and its significance in electrostatics
Concept of electric dipoles and their behavior in electric fields
Key diagrams and graphical representations related to electrostatics
Exam Relevance
Electrostatics is a significant topic in various exams, including CBSE, State Boards, NEET, and JEE. It frequently appears in the form of conceptual questions, numerical problems, and application-based scenarios. Students can expect to encounter questions that require them to apply Coulomb's Law, calculate electric fields, and analyze capacitor circuits. Familiarity with common question patterns will greatly aid in effective exam preparation.
Common Mistakes Students Make
Confusing the concepts of electric field and electric potential
Misapplying Coulomb's Law in multi-charge systems
Neglecting the direction of electric field lines in problem-solving
Overlooking the significance of units and dimensions in calculations
Failing to understand the behavior of capacitors in series and parallel
FAQs
Question: What is the difference between electric field and electric potential? Answer: The electric field is a vector quantity that represents the force experienced by a unit positive charge, while electric potential is a scalar quantity that indicates the potential energy per unit charge at a point in an electric field.
Question: How do capacitors store energy? Answer: Capacitors store energy in the form of an electric field created between their plates when a voltage is applied across them.
Now is the time to strengthen your understanding of electrostatics! Dive into our practice MCQs and test your knowledge on this vital topic. The more you practice, the better prepared you will be for your exams!
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