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Electrostatics & Capacitance Quiz

1. Using Gauss’s law, what is the electric field inside a uniformly charged spherical shell?

Zero everywhere inside the shell Same as outside the shell Non-zero and varies with distance from center

2. The principle of superposition states that:

Forces due to charges add vectorially Charges neutralize each other Electric field lines never intersect

3. Two point charges +q and –q are placed at points A and B, respectively. What is the electric field at the midpoint of AB?

Zero Directed from +q to –q Directed from –q to +q

4. If the distance between two charges is doubled, the force between them changes by a factor of:

2 1/2 1/4

5. Electric field lines:

Begin on negative charges and end on positive charges Begin on positive charges and end on negative charges Are circular

6. The electric flux through a closed surface is zero when:

There is no charge inside the surface Charge is uniformly distributed on the surface Electric field is uniform

7. Which quantity is scalar in nature?

Electric field Electric potential Electric force

8. The potential due to a dipole at a point on the equatorial line is:

Maximum Zero Same as on the axial line

9. The capacitance of an isolated conducting sphere of radius R is proportional to:

1/R R R²

10. The work done in moving a charge in an electric field along an equipotential surface is:

Maximum Zero Depends on path

11. Electric field inside a conductor in electrostatic equilibrium is:

Zero Maximum Same as outside

12. The unit of electric flux in SI is:

Nm²/C N/C Volt

13. The capacitance of a parallel plate capacitor is given by ( C = ε₀ * A / d ). If a dielectric slab of constant ( k ) is inserted fully between plates, the new capacitance will be:

C/k kC C

14. The electrostatic energy stored in a capacitor is given by:

½ CV² CV ½ CV

15. The potential at the center of a uniformly charged spherical shell is:

Zero Same as on the surface Depends on shell thickness

16. When two capacitors are connected in series, the total capacitance is:

Sum of individual capacitances Reciprocal of the sum of reciprocals Product of individual capacitances

17. The energy density of the electric field between capacitor plates is proportional to:

Square of electric field Electric field Inverse of electric field

18. The work done in charging a capacitor depends on:

Charge and voltage only Only voltage Capacitance and voltage

19. Dielectric constant of a material is:

Ratio of capacitances with and without dielectric Inverse of permittivity Ratio of electric fields

20. Equipotential surfaces are always:

Parallel planes Perpendicular to electric field lines Along electric field lines

21. A point charge is placed near a grounded conductor. The potential at the surface of the conductor is:

Zero Infinite Same as the charge

22. The force between two charged plates of a capacitor depends on:

Distance between plates only Charge on plates only Both charge and area of plates

23. The time constant ( \tau ) of an RC circuit is:

RC R/C C/R

24. In a capacitor, an increase in dielectric constant leads to:

Decrease in stored energy Increase in stored energy No change in energy

25. The capacitor in series with resistance and battery is charged to 90% of its maximum charge in time ( t ). The time constant ( \tau ) can be expressed as:

t/2.3 2.3t t/0.9