# Electric Charges And Field VVI Questions

## Electric Charges And Field VVI Subjective Question

Q.1. Define electric dipole moment and write its SI unit.

Ans-  The vector sum of the product of position vector with point charges is known as dipole moment of a charge distribution about the origin.

For two opposite point charges, it is directed from negative to positive charge and equals the product o0f charge and seperation.

SI unit – Cm (coulomb metre) or Asm.

#### Q.2. What are significance of electric lines of force ?

Ans- These lines are used to represent electric field due to a point charge or system of point charges. It is remarkable that these lines are imaginary. They are originated from positive charge and enters the negative charge. Their dense population indicates strong electric field and rare populate indicates weak field.

#### Q.3. What is law of conservation of charge ?

Ans- charges are neither created nor destroyed. There is transfer of charge. Total charge of a system remains conserved.

#### Q.4. What are limitations of coulomb’s law ?

Ans- Limitations of coulomb’s law:

(a) It holds for point charges at rest.

(b) The distance between particles should not be too large.

#### Q.5. Is mass of body changed when it is charged ?

Ans- The charge on a body indicates that whether body has lost electrons or gained electrons. As electron has finite mass. So mass of negatively charged body increases and on being positively charge a body loses some mass.

# Class 12th Physics Electric Charges And Fields Most VVI Objective Questions

### Electric Charges And Field VVI Subjective Question

Q1. The quantum of electric charge in e.s.u. is

(A) 4.78×10⁻¹⁰

(B)1.6×10⁻¹⁹

(C) 2.99×10⁹

(D) -1.6×10⁻¹⁹

Ans:- (A)

Q2. Permittivity of free space is

(A) 9×10⁹ mF⁻¹

(B) 1.6×10⁻¹⁹C

(C) 8.85×10⁻¹²Fm⁻¹

(D) 8.85×10⁻⁹Fm⁻¹

Ans:- (C)

Q3. The unit of electric field intensity is

(A) NC (Newton Coloumb)

(B) NC⁻¹ (Newton/Coloumb)

(C) Vm (Volt m)

(D) CN⁻¹ (Coloumb/Newton)

Ans:- (B)

Q4. 1 Statcoulomb equals….coulomb.

A.3×10⁹

B.3×10⁻⁹

C.1/3×10⁹

D.1/3×10⁻⁹

Q5.The number of electrons that should be removed from an uncharged body to have a charge of one coloumb is

A.6.25×10¹⁸

B.6.25×10⁸

C.6.023×10²³

D.None of these

Q6. Electrostatic field is

(A) conservative

(B) non-conservative

(C) somewhere conservative and somewhere non-conservative

(D) None of these

Ans:- (A)

Q7. Charges A and B attract each other. Charges B and C attract each other. Then A and C.

(A) will attract each other

(B) repel each other

(C) will not effect each other

(D) A , B and C

Ans:- (D)

Q8. 1 Coulomb charge is equal to

A.3×10⁹ e.s.u.

B.9×10⁹ e.s.u.

C.8.85×10⁻¹² e.s.u.

D.None of these

Ans:- (A)

Q9. The charge on a body is written as Q=ne whose e=1.6×10⁻¹⁹ C. The value n will be

A.0,1,2,3….

B.0, ±1, ±2, ±3 , ….

C.0,-1,-2,-3,…

D.None of these

Ans:- (B)

Q10.Force between two charged particles situated at a distance is r. If distance between the two is made half, then the value of electric force will be

(A) 4 F

(B) 2 F

(C) 1/4 F

(D) 1/2

Ans:- (A)

Q11. Coloumbian force is

(A) Central force

(B) Electric force

(C) Both a and b

(D) None of these

Ans:- (C)

Q12. The charge on any substance can not be less than

(A) 1.6×10⁻¹⁹C

(B) 3.2×10⁻¹⁹C

(C) 4.8×10⁻¹⁹

(D) 1C

Ans:- (A)

Q13. When a body is charged ,its mass

(A) Increases

(B) Decreases

(C) Remains same

(D) May increase or decrease

Ans:- (D)

Q14. The dimensional formula of electric field intensity is

(A) [MLT⁻²A⁻¹]

(B) [MLT⁻³A⁻¹]

(C)ML²T⁻³A⁻²]

(D) [ML²T²A²]

Ans:- (B)

Q15. Which of the laws gives the force between two charges at rest ?

(A) Gauss theorem

(B) Kirchhoff’s rules

(C) Coulomb’s law

Ans:- (C)

Q16. The value of 1/4πε₀ is

(A) 9×10⁹ Nm²C⁻²

(B) 8.85×10⁻¹² Nm²C⁻²

(C) 9×10⁻⁹ Nm²C⁻²

(D) zero

ANs:- (B)

Q17. There are two identical spheres A and B. A is given +Q charge and B is given -Q charge

(A) Mass of A increases

(B) Mass of B increases

(C) No effect on Mass

(D) None

Ans:- (B)

Q18. The S.I. unit of electric flux is

(A) Weber

(B) Nm²C⁻¹

(C) Newton/m

(D) m²/s

Ans:- (B)

Q19. The total charge on a electric dipole is

(A) Zero

(B) Negative

(C) Positive

(D) Infinite

Ans:- (A)

Q20. The electric field intensity at infinite distance from an electric charge is

(A) Infinite

(B) Zero

(C) 9×10⁹V/m

(D) None of these

Ans:- (B)

Q21. Unit of surface density of charge is

(A) Coulomb/meter²

(B) Newton meter⁻¹

(C) Coulomb Volt⁻¹

(D) Coulomb meter

Ans:- (A)

Q22. The electric field at a point near an infinite thin sheet of charged conductor is

(A) ∈₀σ

(B) σ/∈₀

(C) σ/2∈₀

(D) σ∈₀/2

Ans:- (C)

Q23. A surface encloses an electric dipole. The total electric flux over the surface is

(A) Infinite

(B) Zero

(C) q/∈₀

(D) None of these

Ans:- (B)

Q24. When a soap bubble is charged, its radius

(A) Increases

(B) Decreases

(C) Remains the same

(D) Becomes zero

Ans:- (A)

Q25. The electric field intensity inside a hollow spherical charged conductor is

(A) Infinite

(B) Zero

(C) Positive and greater than 1

(D) None

Ans:- (B)

Q26. When a body becomes negatively charged, its mass

(A) Decreases

(B) Increases

(C) Remains the same

(D) None of these

Ans:- (B)

Q27. The value of electric field inside a charged spherical conductor is

(A) σ/∈₀

(B) zero

(C) ∈₀σ

(D) σ²/∈₀

Ans:- (B)

Q28. Minimum number of capacitors of 2μF each required to obtain a capacitance of 5μF will be

(A) 4

(B) 3

(C) 5

(D) 6

Ans:- (A)

Q29. Surface charge density of a conductor is σ. Electric field near it is

(A) σ/2∈₀

(B) σ/∈₀

(C) 2σ/∈₀

(D) σ/3∈₀

Ans:- (B)

Q30. Force of attraction between the plates of a parallel plate capacitor is

(A) -q²/2∈₀Ak

(B) q³/2∈₀A

(C) q/∈₀Ak

(D) q²/2∈₀A²k

Ans:- (A)

### 4 thoughts on “Electric Charges And Field VVI Questions | Physics VVI Objective Question Bihar Board | Bihar Board Class 12th Physics”

1. class 12th mathematics Hindi medium class 12th mathematics Hindi English grammar study physics Hindi medium all subject