Class 12 Physics Electric Charges and Fields MCQs (Difficulty-wise) with Answers
Use this difficulty-wise set to revise Electric Charges and Fields step-by-step. Start with definitions (charge, conductors/insulators), then move to superposition and dipoles, and finally practise higher-level ideas like dipole field variation and continuous charge distributions. Each question has a short explanation so you can correct mistakes quickly.
Easy (Level 1)
Question 1
Quantisation of charge means:
A. Charge can take any fractional value
B. Charge on a body is an integral multiple of $e$
C. Charge exists only on conductors
D. Charge is always positive
Correct Answer: B
Explanation: $q = ne$, where $n$ is an integer and $e$ is the elementary charge.
Question 2
In the gold-leaf electroscope, divergence of leaves mainly shows:
A. Presence of charge (and roughly how much)
B. Temperature of the body
C. Pressure of surrounding air
D. Mass of the body
Correct Answer: A
Explanation: Like charges on the leaves repel and the separation increases with more charge.
Question 3
Why does a metal spoon usually not remain charged when you try to charge it by rubbing?
A. Metal is an insulator
B. Charge leaks through your body to earth because metal is a conductor
C. Metals cannot have electrons
D. Rubbing creates no charge transfer
Correct Answer: B
Explanation: Conductors allow charge to move easily, so it quickly flows away unless insulated from earth.
Medium (Level 2)
Revision Tip: For direction-based questions, mark: (1) direction of electric field is for a positive test charge, (2) field lines never intersect.
Question 4
Assertion (A): Electric field lines around a positive point charge point radially outward. Reason (R): The electric field at any point is along the tangent to the field line at that point.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
Correct Answer: A
Explanation: Field lines show direction of $\vec{E}$; outward for a positive charge.
Question 5
An electric dipole has charges $+q$ and $-q$ separated by $2a$. The dipole moment vector $\vec{p}$ is directed:
A. From $+q$ to $-q$
B. From $-q$ to $+q$
C. Perpendicular to the line joining the charges
D. In random direction
Correct Answer: B
Explanation: By convention, $\vec{p}$ points from negative to positive charge.
Question 6
A dipole is placed in a uniform electric field. Which statement is correct?
A. Net force is zero and torque is zero
B. Net force is non-zero but torque is zero
C. Net force is zero but torque tends to align $\vec{p}$ with $\vec{E}$
D. Both net force and torque are always non-zero
Correct Answer: C
Explanation: Equal and opposite forces act on the charges (net force zero), but they form a couple that produces torque.
Hard (Level 3)
Revision Tip: When a question says “continuous distribution”, think “integrate small pieces” and use superposition.
Question 7
At large distances $r$ ($r \gg 2a$) from an electric dipole, the electric field magnitude varies as:
A. $\frac{1}{r}$
B. $\frac{1}{r^2}$
C. $\frac{1}{r^3}$
D. Constant
Correct Answer: C
Explanation: Dipole field falls faster than a point charge field: $E_{\text{dipole}} \propto \frac{1}{r^3}$.
Question 8
Electric field due to a continuous charge distribution can be found by:
A. Ignoring Coulomb’s law
B. Adding contributions of small charge elements and integrating
C. Using only total charge irrespective of distribution
D. Using only the nearest charge element
Correct Answer: B
Explanation: Break the distribution into small elements $dq$ and add $d\vec{E}$ using superposition.
Question 9
The fundamental reason bodies get charged on rubbing is:
A. Creation of new charges
B. Transfer of electrons
C. Transfer of protons
D. Destruction of atoms
Correct Answer: B
Explanation: Electrons can transfer between materials; charges are not created or destroyed.
Question 10
The solid angle $d\Omega$ subtended by area element $dS$ at distance $r$ from a point is:
A. $d\Omega = dS,r^2$
B. $d\Omega = \frac{dS}{r^2}$
C. $d\Omega = \frac{r}{dS}$
D. $d\Omega = dS,r$
Correct Answer: B
Explanation: $d\Omega = \frac{dS}{r^2}$.
Want a mixed set for quick revision? Go back to: Class 12 Physics Electric Charges and Fields MCQs (Mixed).
If you’re short on time, do Easy + Medium first, then attempt only 2–3 Hard questions and revise the explanations.