Electric Charges and Fields - Class 12 Physics Notes

50 Important MCQs

1. Which of the following is a property of electric charge?
   ✔ It is quantized
   ❌ It is continuous
   ❌ It is only negative
   ❌ It cannot be transferred
2. Two charges repel each other. This means:
   ✔ Both charges are of the same type
   ❌ Both charges are of opposite types
   ❌ One charge is larger than the other
   ❌ Charges are neutral
3. Coulomb’s law is similar to which other physical law?
   ✔ Newton’s law of universal gravitation
   ❌ Hooke’s law
   ❌ Bernoulli’s equation
   ❌ Ohm’s law
4. The unit of electric field is:
   ✔ Newton per coulomb
   ✔ Volt per meter
   ❌ Both a and b
   ❌ Joule per coulomb
5. Electric field lines never:
   ❌ Start from positive charges
   ❌ End at negative charges
   ✔ Cross each other
   ❌ Form loops
6. The net electric field at a point is the vector sum of the fields due to individual charges. This is called:
   ❌ Conservation of energy
   ✔ Principle of superposition
   ❌ Coulomb's law
   ❌ Faraday’s law
7. Gauss’s law is useful in calculating fields due to:
   ❌ Irregular shapes
   ✔ Symmetric charge distributions
   ❌ Magnetic materials
   ❌ None of the above
8. A hollow conducting sphere has electric field inside equal to:
   ✔ Zero
   ❌ Maximum at the center
   ❌ Depends on charge amount
   ❌ Infinity
9. Electric flux is defined as:
   ✔ Electric field multiplied by area
   ❌ Charge multiplied by distance
   ❌ Potential difference multiplied by charge
   ❌ Current times resistance
10. The force between two charges varies inversely as the:
    ✔ Square of the distance between them
    ❌ Distance between them
    ❌ Cube of the distance between them
    ❌ Fourth power of distance
11. The SI unit of charge is:
    ✔ Coulomb
    ❌ Ampere
    ❌ Newton
    ❌ Joule
12. Electric field lines inside a conductor are:
    ✔ Zero
    ❌ Constant
    ❌ Infinite
    ❌ Depends on external field
13. When a conductor is in electrostatic equilibrium, the charge resides on:
    ✔ The surface
    ❌ The volume
    ❌ The center
    ❌ Everywhere equally
14. The force on a charge placed in an electric field is:
    ✔ qE
    ❌ E/q
    ❌ q/E
    ❌ E×q²
15. Which of the following affects the force between two charges?
    ❌ Magnitude of charges
    ❌ Distance between charges
    ✔ Both a and b
    ❌ None of the above
16. If the distance between two charges is doubled, the force becomes:
    ❌ Four times larger
    ❌ Half
    ✔ One fourth
    ❌ Same
17. The principle that electric charges can be neither created nor destroyed is called:
    ✔ Conservation of charge
    ❌ Ohm’s law
    ❌ Newton’s law
    ❌ Ampere’s law
18. Electric field lines point from:
    ✔ Positive to negative charges
    ❌ Negative to positive charges
    ❌ Parallel to magnetic field
    ❌ Any random direction
19. Gauss’s law relates electric flux to:
    ❌ The surface area
    ✔ The enclosed charge
    ❌ The magnetic field
    ❌ The potential difference
20. Which of the following materials is a conductor?
    ✔ Copper
    ❌ Rubber
    ❌ Glass
    ❌ Wood
21. The force between two charges is independent of:
    ❌ Medium between them
    ❌ Distance between them
    ❌ Both charge magnitudes
    ✔ Temperature
22. Electric flux through a closed surface with no enclosed charge is:
    ✔ Zero
    ❌ Infinite
    ❌ Constant
    ❌ Depends on area
23. Field lines outside a charged conductor are always:
    ✔ Perpendicular to the surface
    ❌ Parallel to the surface
    ❌ Tangential to the surface
    ❌ Circular
24. Electric field inside a conductor is zero because:
    ✔ Charges rearrange to cancel internal fields
    ❌ Electric field does not penetrate conductors
    ❌ Conductors are always neutral
    ❌ None of the above
25. The electric field due to a point charge is inversely proportional to:
    ✔ The square of the distance
    ❌ The distance
    ❌ The cube of the distance
    ❌ None of the above
26. The total electric flux through a spherical surface enclosing a point charge depends on:
    ✔ The charge enclosed
    ❌ The radius of the sphere
    ❌ The area of the surface
    ❌ The potential difference
27. Which of the following is true about electric field lines?
    ✔ They never intersect
    ❌ They can cross at points
    ❌ They are always circular
    ❌ They start and end at the same point
28. A positively charged sphere will have electric field lines:
    ✔ Pointing outward
    ❌ Pointing inward
    ❌ Circular
    ❌ Parallel
29. In a uniform electric field, the field lines are:
    ✔ Equally spaced and parallel
    ❌ Converging
    ❌ Diverging
    ❌ Circular
30. Electric field inside a cavity of a conductor is:
    ✔ Zero
    ❌ Depends on shape
    ❌ Maximum at the boundary
    ❌ Non-zero and constant
31. Coulomb’s law applies only to:
    ✔ Point charges
    ❌ Spherical charges
    ❌ Any object
    ❌ Magnetic materials
32. If one charge is doubled, the force becomes:
    ✔ Double
    ❌ Half
    ❌ Unchanged
    ❌ Zero
33. A non-conducting material is called:
    ✔ Insulator
    ❌ Conductor
    ❌ Semiconductor
    ❌ Dielectric
34. Electric flux is measured in:
    ✔ Nm²/C
    ❌ V/m
    ❌ A/m
    ❌ None of the above
35. The electric field at a point is defined as:
    ✔ Force per unit charge
    ❌ Work per unit charge
    ❌ Charge per unit area
    ❌ None of the above
36. Which of the following is an effect of an electric field on a conductor?
    ✔ Charges redistribute on the surface
    ❌ It generates magnetic fields
    ❌ It reduces the temperature
    ❌ None of the above
37. The total electric flux through any closed surface depends on:
    ✔ The net charge enclosed
    ❌ The shape of the surface
    ❌ The material of the surface
    ❌ The external fields
38. The electric field inside a uniformly charged sphere at its center is:
    ✔ Zero
    ❌ Maximum
    ❌ Depends on the radius
    ❌ Infinite
39. Which of the following is true about electric lines of force?
    ✔ They start from positive and end at negative charges
    ❌ They form closed loops
    ❌ They never start or end
    ❌ They are parallel to magnetic field lines
40. If two charges are of equal magnitude but opposite signs, the force between them:
    ✔ Is attractive
    ❌ Is repulsive
    ❌ Depends on velocity
    ❌ Is zero
41. The direction of electric field at a point due to a positive charge is:
    ✔ Away from the charge
    ❌ Toward the charge
    ❌ Perpendicular to the charge
    ❌ Along the magnetic field
42. Which factor does not affect the electric force between two charges?
    ❌ Magnitude of the charges
    ❌ Distance between the charges
    ❌ Medium between them
    ✔ Their velocity
43. The total electric flux depends on:
    ✔ Net enclosed charge
    ❌ Surface area only
    ❌ Shape of the surface only
    ❌ External field only
44. The electric field is strongest where:
    ❌ Field lines are widely spaced
    ✔ Field lines are close together
    ❌ Field lines are curved
    ❌ There are no field lines
45. Gauss’s law is derived from:
    ❌ Conservation of momentum
    ❌ Ohm’s law
    ✔ Coulomb’s law
    ❌ Faraday’s law
46. Which of the following statements is true for a conductor in electrostatic equilibrium?
    ✔ The electric field inside is zero
    ❌ The field is maximum at the center
    ❌ Charges are uniformly distributed throughout the volume
    ❌ Field lines are closed loops inside the conductor
47. A charged conductor has maximum electric field at:
    ❌ Its center
    ❌ Anywhere on its surface
    ✔ Sharp edges or points
    ❌ Away from the surface
48. The force between two charges is independent of:
    ❌ Their separation
    ❌ Their magnitude
    ✔ Their shape
    ❌ The medium between them
49. When a neutral conductor is placed in an external electric field, charges within it:
    ✔ Rearrange themselves
    ❌ Remain stationary
    ❌ Get destroyed
    ❌ Increase in number
50. Electric flux through a closed surface is proportional to:
    ❌ Surface area
    ✔ Enclosed charge
    ❌ Temperature
    ❌ Electric current