## Objective Questions on Electrostatic Field

Objective Questions on Electrostatic Field, MCQ on electric charges and fields, MCQ on electrostatics, electric field multiple-choice question ans answer.

### Multiple Choice Questions

- The proportionality constant in Coulomb’s law has unit of

- Farads
- Farads/meter
- Newton
- meter/Farad

**Answer:** meter/Farad

2. The value of proportionality constant in Coulomb’s law is

- 9 × 10
^{9} - 9 × 10
^{–9} - 8.854 × 10
^{–12} - 1/36 π × 10
^{9}

**Answer:** 9 × 10^{9}

3. The force magnitude between Q_{1} = 1C and Q_{2} = 1C when they are separated by 1 m in free space is

- 9 × 10
^{9}N - 8.854 × 10
^{–12}N - 1/36 π × 10
^{-9}N - 9 × 10
^{–9}N

**Answer:** 9 × 10^{9} N

4. Potential has the unit of

- Joules/Coulomb
- Joules
- Joules/m
^{3} - Joules/m
^{2}

**Answer:** Joules/Coulomb

5. The unit of electric flux is

- Coulomb
- Coulomb/metre
- Weber
- Weber/m
^{2}

**Answer:** Coulomb

6. The unit of electric field is

- Newton
- Coulomb/Newton
- Newton/Coulomb
- Coulomb/metre

**Answer:** Newton/Coulomb

7. Potential at all the points on the surface of a conductor is

- the same
- not the same
- zero
- infinity

**Answer:** the same

8. Gradient of the potential and an equipotential surface

- have the same direction
- have opposite directions
- are orthogonal to each other
- have no directional relation

**Answer:** are orthogonal to each other

9. The Laplacian operator, ∇^{2}

- has unit of m
^{2} - is a vector operator
- has unit of 1/m
^{2} - has no unit

**Answer:** has unit of 1/m^{2}

10. Laplace’s equation has

- two solutions
- infinite solutions
- no solution
- only one solution

**Answer:** only one solution

11. The surface charge density in a good dielectric is

- zero
- ρ
_{s} - infinity
- – ρ
_{s}

**Answer:** zero

12. Gauss’s law in point form is

- \bigtriangledown .D=\rho _{\upsilon }
- \bigtriangledown .D=\rho _{s}
- \bigtriangledown .D=Q
- \bigtriangledown D=\rho _{\upsilon }

**Answer:** \bigtriangledown .D=\rho _{\upsilon }

13. Poisson’s equation is

- \bigtriangledown ^{2}V=\rho _{\upsilon}/\epsilon
- \bigtriangledown ^{2}V=-\rho _{\upsilon}/\epsilon
- \bigtriangledown ^{2}V=-\rho _{\upsilon}
- \bigtriangledown ^{2}V=-\dot{\rho _{\upsilon}}/\epsilon

**Answer:** \bigtriangledown ^{2}V=-\rho _{\upsilon}/\epsilon

14. Electric flux lines

- originate at (+)ve charge
- originate at (–)ve charge
- are closed loops
- originate at (+)ve charge and also terminate at (+)ve charge

**Answer:** originate at (+)ve charge

15. Unit of electric flux is

- Coulomb
- Weber
- Tesla
- Weber/m

**Answer:** Coulomb