# Physics Class 12th Chapter 1 Electric Charges And Fields VVI Objective Questions | Physics Objective Question Bihar Board | 12th Physics Objective Question Bihar Board English Medium

(B)1.6×10⁻¹⁹

(C) 2.99×10⁹

(D) -1.6×10⁻¹⁹

Ans:- (A)

### Q.2. 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)

### Q.3. 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)

A.3×10⁹

B.3×10⁻⁹

C.1/3×10⁹

D.1/3×10⁻⁹

Ans:- (D)

A.6.25×10¹⁸

B.6.25×10⁸

C.6.023×10²³

D.None of these

Ans:- (A)

### Q.6. Electrostatic field is

(A) conservative

(B) non-conservative

(C) somewhere conservative and somewhere non-conservative

(D) None of these

Ans:- (A)

Q.7. 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)

### Q.8. 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)

### Q.9. 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)

(A) 4 F

(B) 2 F

(C) 1/4 F

(D) 1/2

Ans:- (A)

### Q.11. Coloumbian force is

(A) Central force

(B) Electric force

(C) Both a and b

(D) None of these

Ans:- (C)

(A) 1.6×10⁻¹⁹C

(B) 3.2×10⁻¹⁹C

(C) 4.8×10⁻¹⁹

(D) 1C

Ans:- (A)

### Q.13. When a body is charged ,its mass

(A) Increases

(B) Decreases

(C) Remains same

(D) May increase or decrease

Ans:- (D)

(A) [MLT⁻²A⁻¹]

(B) [MLT⁻³A⁻¹]

(C)ML²T⁻³A⁻²]

(D) [ML²T²A²]

Ans:- (B)

### Q.15. 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)

### Q.16. 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)

### Q.17. 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)

(A) Weber

(B) Nm²C⁻¹

(C) Newton/m

(D) m²/s

Ans:- (B)

(A) Zero

(B) Negative

(C) Positive

(D) Infinite

Ans:- (A)

### Q.20. 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)

### Q.21. Unit of surface density of charge is

(A) Coulomb/meter²

(B) Newton meter⁻¹

(C) Coulomb Volt⁻¹

(D) Coulomb meter

Ans:- (A)

(A) ∈₀σ

(B) σ/∈₀

(C) σ/2∈₀

(D) σ∈₀/2

Ans:- (C)

### Q.23. 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)

### Q.24. When a soap bubble is charged, its radius

(A) Increases

(B) Decreases

(C) Remains the same

(D) Becomes zero

Ans:- (A)

### Q.25. 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)

### Q.26. When a body becomes negatively charged, its mass

(A) Decreases

(B) Increases

(C) Remains the same

(D) None of these

Ans:- (B)

(A) σ/∈₀

(B) zero

(C) ∈₀σ

(D) σ²/∈₀

Ans:- (B)

(A) 4

(B) 3

(C) 5

(D) 6

Ans:- (A)

(A) σ/2∈₀

(B) σ/∈₀

(C) 2σ/∈₀

(D) σ/3∈₀

Ans:- (B)

### Q.30. 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)

Q.31. If the surface is parallel to the electric field , in this case the electric flux is
(A) maximum
(B) zero
(C) infinity
(D) none of these
Ans:- (B)
Q.32. Debye is the unit of
(A) charge
(B) polarization
(C) electric dipole moment
(D) none
Ans:- (C)
Q.33. The dielectric constant of an insulator can not be
(A) 1.5
(B) 3
(C) 4.5
(D) infinity
Ans:- (D)
Q.34. The permittivity of vaccum is
(A) 1
(B) more than 1
(C) less than 1 but not zero
(D) zero
Ans:- (C)
Q.35. The direction of dipole moment is
(A) from negative charge to positive charge
(B) from positive charge to negative charge
(C) perpendicular to the axis
(D) none of these
Ans:- (A)
Q.36. If the surface is parallel to the electric field, in this case the electric flux is
(A) maximum
(B) zero
(C) infinity
(D) none of these
Ans:- (B)
Q.37. If sphere of bad conductor is given charge then it is distributed on
(A) surface
(B) surface and also inside the surface
(C) only inside the surface
(D) none of these
Ans:- (D)
Q.38. Electric dipole moment is
(A) vector quantity
(B) scalar quantity
(C) ratio
(D) none of these
Ans:- (A)
Q.39. A charge is enclosed by the surface of radius r.  if the radius is increased twice of the previous them electric flux will be
(A) increased
(B) decreased
(C) remains unchanged
(D) none of these
Ans:- (C)
Q.40. By which method electric charge can produce is
(A) by friction
(B) by induction
(C) both ‘A’ and ‘B’
(D) all of above
Ans:- (C)