Gauss’s Law & Flux | 1 MARKS QUESTION 👀 | PHYSICS | APNA CAREER

 

Gauss’s Law & Flux

1 MARKS QUESTION 👀

1. What is electric flux?

Answer: Measure of electric field passing through a surface

Explanation: Indicates number of field lines.

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2. What is symbol of electric flux?

Answer: 

$\mathrm{\Phi }$

Explanation: Greek letter phi.

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3. What is formula of electric flux?

Answer:

$\mathrm{\Phi }=EA\cos \theta$

Explanation: Depends on area and angle.

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4. What is SI unit of electric flux?

Answer: 

$N{m}^2\mathrm{/}C$

Explanation: Derived unit.

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5. What is Gauss’s Law?

Answer: Total flux = enclosed charge / ε₀

Explanation: Fundamental electrostatics law.

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6. Write Gauss’s Law formula.

Answer:

$\mathrm{\Phi }=\frac{Q_{enc}}{{\epsilon }_0}$

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7. What is a Gaussian surface?

Answer: Imaginary closed surface

Explanation: Used to apply Gauss law.

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8. What is flux when field is perpendicular to surface?

Answer: Maximum

Explanation: 

$\theta =0^{\circ }$

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9. What is flux when field is parallel to surface?

Answer: Zero

Explanation: 

$\theta ={90}^{\circ }$

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10. What is ε₀?

Answer: Permittivity of free space

Explanation: Constant value.

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11. What is value of ε₀?

Answer: 

$8.85\times {10}^{-12}F\mathrm{/}m$

Explanation: Standard constant.

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12. What type of quantity is electric flux?

Answer: Scalar

Explanation: No direction.

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13. What is flux through closed surface with no charge inside?

Answer: Zero

Explanation: No enclosed charge.

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14. What is area vector direction?

Answer: Normal to surface

Explanation: Outward for closed surface.

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15. What is closed surface?

Answer: Surface enclosing volume

Explanation: No open edges.

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16. What is open surface?

Answer: Surface with boundary

Explanation: Does not enclose volume.

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17. What does positive flux indicate?

Answer: Outward field lines

Explanation: Leaving surface.

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18. What does negative flux indicate?

Answer: Inward field lines

Explanation: Entering surface.

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19. What is Gauss law based on?

Answer: Inverse square law

Explanation: Coulomb’s law.

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20. What does flux depend on?

Answer: Field, area, angle

Explanation: From formula.

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🔹 21–35 (Conceptual Understanding)

21. Does flux depend on shape of surface?

Answer: No

Explanation: Depends only on enclosed charge.

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22. What is flux if charge lies outside surface?

Answer: Zero

Explanation: Not enclosed.

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23. What is flux proportional to?

Answer: Electric field strength

Explanation: Stronger field → more flux.

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24. What is flux through sphere enclosing charge Q?

Answer:

$$$$Φ=Qε0

Explanation: Gauss law.

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25. What is flux through cube enclosing charge?

Answer: Same as sphere

Explanation: Shape independent.

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26. What is electric field inside conductor?

Answer: Zero

Explanation: Electrostatic equilibrium.

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27. Where do charges reside in conductor?

Answer: On surface

Explanation: Repulsion spreads charges.

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28. What is field direction at conductor surface?

Answer: Perpendicular

Explanation: No tangential component.

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29. What is flux for uniform field?

Answer: Easy to calculate

Explanation: Constant field.

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30. What is net flux for equal inward and outward lines?

Answer: Zero

Explanation: Cancel out.

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31. What is Gaussian surface used for?

Answer: Calculating electric field

Explanation: Simplifies problems.

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32. What is symmetry requirement in Gauss law?

Answer: High symmetry

Explanation: For easy application.

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33. What is flux for curved surface?

Answer: Depends on angle

Explanation: Orientation matters.

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34. What is total flux through closed surface?

Answer: Algebraic sum

Explanation: Add all contributions.

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35. What is electric field lines relation to flux?

Answer: Flux ∝ number of lines

Explanation: Representation.

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🔹 36–50 (Applications & Key Results)

36. What is electric field due to spherical charge using Gauss law?

Answer:

$E=\frac{1}{4\pi {\epsilon }_0}\frac{Q}{r^2}$

Explanation: Same as point charge.

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37. What is electric field inside hollow sphere?

Answer: Zero

Explanation: No enclosed charge.

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38. What is electric field outside sphere?

Answer: Like point charge

Explanation: Radial field.

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39. What is field due to infinite plane sheet?

Answer: Constant

Explanation: Independent of distance.

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40. What is flux through plane sheet?

Answer: Depends on area

Explanation: Uniform field.

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41. What is electric field due to infinite line charge?

Answer: Decreases with distance

Explanation: Cylindrical symmetry.

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42. What is Gaussian surface for line charge?

Answer: Cylinder

Explanation: Matches symmetry.

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43. What is Gaussian surface for sphere?

Answer: Sphere

Explanation: Radial symmetry.

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44. What is Gaussian surface for plane?

Answer: Pillbox

Explanation: Flat symmetry.

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45. What is field inside cavity of conductor?

Answer: Zero

Explanation: Shielding.

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46. What is flux through hemisphere?

Answer: Half of sphere

Explanation: Symmetry.

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47. What is importance of Gauss law?

Answer: Simplifies field calculation

Explanation: Powerful tool.

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48. What is flux independent of?

Answer: Surface shape

Explanation: Depends only on charge.

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49. What is electric field relation with flux?

Answer: Field produces flux

Explanation: Field lines pass through area.

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50. What is summary of Gauss’s Law?

Answer: Flux depends only on enclosed charge

Explanation: Fundamental principle.

51. What is electric field inside a conductor?

Answer: Zero

Explanation: Charges rearrange to cancel field.

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52. What is electric field just outside a conductor?

Answer: Perpendicular to surface

Explanation: No tangential component.

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53. What is flux through closed surface enclosing no charge?

Answer: Zero

Explanation: From Gauss’s law.

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54. What is flux through closed surface enclosing charge Q?

Answer:

$\mathrm{\Phi }=\frac{Q}{{\epsilon }_0}$

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55. What is flux if charge is outside the surface?

Answer: Zero

Explanation: Not enclosed.

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56. What is Gaussian surface for spherical symmetry?

Answer: Sphere

Explanation: Matches symmetry.

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57. What is Gaussian surface for line charge?

Answer: Cylinder

Explanation: Cylindrical symmetry.

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58. What is Gaussian surface for plane sheet?

Answer: Pillbox

Explanation: Flat symmetry.

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59. What is electric field due to spherical charge?

Answer:

$E=\frac{1}{4\pi {\epsilon }_0}\frac{Q}{r^2}$

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60. What is field inside hollow sphere?

Answer: Zero

Explanation: No enclosed charge.

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61. What is field outside charged sphere?

Answer: Like point charge

Explanation: Radial field.

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62. What is electric field due to infinite plane sheet?

Answer: Constant

Explanation: Independent of distance.

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63. What is field due to infinite line charge?

Answer: Decreases with distance

Explanation: 

$\propto \frac{1}{r}$

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64. What is flux through hemisphere?

Answer: Half of total sphere flux

Explanation: Symmetry.

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65. What is flux through cube enclosing charge?

Answer: Same as any shape

Explanation: Shape independent.

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66. What is flux proportional to enclosed charge?

Answer: Directly proportional

Explanation: From Gauss law.

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67. What is flux independent of?

Answer: Surface shape

Explanation: Only depends on charge.

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68. What is direction of area vector for closed surface?

Answer: Outward

Explanation: Convention.

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69. What is sign of flux for outward field lines?

Answer: Positive

Explanation: Leaving surface.

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70. What is sign of flux for inward field lines?

Answer: Negative

Explanation: Entering surface.

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🔹 71–85 (Field & Symmetry)

71. What is condition to apply Gauss law easily?

Answer: Symmetry

Explanation: Simplifies calculation.

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72. What type of symmetry needed?

Answer: Spherical, cylindrical, planar

Explanation: Common cases.

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73. What is electric field inside cavity of conductor?

Answer: Zero

Explanation: Shielding effect.

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74. What is flux through any closed surface?

Answer: Depends on enclosed charge

Explanation: Gauss law.

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75. What is electric field inside solid conductor?

Answer: Zero

Explanation: Electrostatic equilibrium.

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76. What happens to charges in conductor?

Answer: Move to surface

Explanation: Repulsion.

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77. What is electric field at sharp edges?

Answer: Very high

Explanation: Charge concentration.

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78. What is flux relation with field lines?

Answer: Proportional

Explanation: More lines → more flux.

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79. What is electric field direction at surface?

Answer: Normal

Explanation: Perpendicular.

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80. What is flux if equal lines enter and leave?

Answer: Zero

Explanation: Cancel out.

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81. What is electric field inside charged shell?

Answer: Zero

Explanation: Symmetry.

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82. What is electric field outside shell?

Answer: Like point charge

Explanation: From center.

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83. What is flux through curved surface?

Answer: Depends on angle

Explanation: Orientation matters.

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84. What is electric field due to charge distribution?

Answer: Depends on symmetry

Explanation: Shape matters.

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85. What is flux additive property?

Answer: Yes

Explanation: Sum of contributions.

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🔹 86–100 (Advanced Understanding)

86. What is differential form of Gauss law?

Answer:

$\mathrm{\nabla }\cdot E=\frac{\rho }{{\epsilon }_0}$

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87. What is divergence of electric field?

Answer: Measure of field source

Explanation: Related to charge density.

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88. What is volume charge density symbol?

Answer: 

$\rho$

Explanation: Charge per volume.

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89. What is flux through small area?

Answer: 

$d\mathrm{\Phi }=EdA\cos \theta$

Explanation: Differential form.

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90. What is Gauss law integral form?

Answer:

$$$$∮E⋅dA=Qε0

∮E⋅dA=

ε

0​

Q​

Explanation: Total flux.

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91. What is field due to uniform sphere inside?

Answer: Varies with radius

Explanation: Not zero.

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92. What is field at center of sphere?

Answer: Zero

Explanation: Symmetry.

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93. What is flux for point charge at center?

Answer: Same for all surfaces

Explanation: Shape independent.

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94. What is electric field at boundary?

Answer: Discontinuous

Explanation: Changes across surface.

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95. What is tangential component of field at boundary?

Answer: Continuous

Explanation: Does not change.

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96. What is normal component of field at boundary?

Answer: Discontinuous

Explanation: Depends on charge.

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97. What is electric field lines nature?

Answer: Continuous

Explanation: Do not break.

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98. What is flux through cube face (charge at center)?

Answer: Equal on all faces

Explanation: Symmetry.

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99. What is flux per face of cube?

Answer: 

$\frac{Q}{6{\epsilon }_0}$

Explanation: Total divided equally.

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100. What is summary of Gauss’s Law?

Answer: Flux depends only on enclosed charge

Explanation: Fundamental electrostatic principle.

101. What is electric flux through a closed surface?

Answer: Depends only on enclosed charge

Explanation: Independent of shape.

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102. What is Gauss’s law in integral form?

Answer:

$\oint \vec{E}\cdot d\vec{A}=\frac{Q}{{\epsilon }_0}$

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103. What is divergence of electric field?

Answer: Measure of source of field

Explanation: Related to charge density.

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104. What is Gauss’s law in differential form?

Answer:

$\mathrm{\nabla }\cdot E=\frac{\rho }{{\epsilon }_0}$

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105. What is volume charge density?

Answer: Charge per unit volume

Explanation: Represented by 

$\rho$

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106. What is surface charge density symbol?

Answer: 

$\sigma$

Explanation: Charge per unit area.

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107. What is linear charge density symbol?

Answer: 

$\lambda$

Explanation: Charge per unit length.

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108. What is electric flux through open surface?

Answer: Depends on orientation

Explanation: Not fixed.

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109. What is net flux through closed surface always?

Answer: Enclosed charge / ε₀

Explanation: Gauss law.

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110. What is flux through surface if E = 0?

Answer: Zero

Explanation: No field.

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111. What is field inside cavity (no charge)?

Answer: Zero

Explanation: Shielding.

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112. What is field inside cavity (with charge)?

Answer: Non-zero

Explanation: Due to internal charge.

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113. What is electric field symmetry required for Gauss law?

Answer: High symmetry

Explanation: Simplifies calculations.

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114. What is flux through cube enclosing charge Q?

Answer: 

$Q\mathrm{/}{\epsilon }_0$

Explanation: Shape independent.

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115. What is flux per face of cube (charge at center)?

Answer: 

$Q\mathrm{/}6{\epsilon }_0$

Explanation: Equal distribution.

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116. What is electric field inside uniformly charged sphere?

Answer: Varies with radius

Explanation: Not constant.

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117. What is electric field at center of sphere?

Answer: Zero

Explanation: Symmetry.

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118. What is electric field outside uniformly charged sphere?

Answer: Like point charge

Explanation: Radial field.

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119. What is flux through sphere due to external charge?

Answer: Zero

Explanation: Not enclosed.

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120. What is electric field at boundary of conductor?

Answer: Discontinuous (normal component)

Explanation: Due to surface charge.

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🔹 121–135 (Application & Properties)

121. What is tangential component of electric field at boundary?

Answer: Continuous

Explanation: Does not change.

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122. What is normal component of electric field at boundary?

Answer: Discontinuous

Explanation: Depends on surface charge.

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123. What is electric field due to infinite line charge formula?

Answer:

$$$$E=λ2πε0r

E=

2πε

0​

r

λ​

Explanation: Cylindrical symmetry.

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124. What is electric field due to infinite plane sheet formula?

Answer:

$$$$E=σ2ε0

E=

2ε

0​

σ​

Explanation: Constant field.

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125. What is flux through hemisphere?

Answer: Half of total sphere flux

Explanation: Symmetry.

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126. What is Gaussian surface choice based on?

Answer: Symmetry

Explanation: Simplifies integration.

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127. What is electric field inside conductor in electrostatics?

Answer: Zero

Explanation: Charges rearrange.

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128. Where does excess charge reside in conductor?

Answer: On surface

Explanation: Repulsion effect.

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129. What is electric field at sharp edges?

Answer: Very high

Explanation: Charge concentration.

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130. What is flux through any closed surface?

Answer: Independent of surface shape

Explanation: Depends only on charge.

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131. What is electric field lines density indicate?

Answer: Field strength

Explanation: Denser → stronger.

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132. What is electric field direction at surface?

Answer: Normal

Explanation: Perpendicular.

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133. What is flux if equal lines enter and leave?

Answer: Zero

Explanation: Cancel out.

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134. What is Gauss law useful for?

Answer: Calculating electric field

Explanation: For symmetric systems.

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135. What is flux sign convention?

Answer: Outward positive

Explanation: Standard rule.

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🔹 136–150 (Quick Revision Q&A)

136. Flux depends on?

Answer: Enclosed charge

Explanation: From Gauss law.

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137. Flux unit?

Answer: 

$N{m}^2\mathrm{/}C$

Explanation: SI unit.

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138. Electric field inside conductor?

Answer: Zero

Explanation: Electrostatic equilibrium.

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139. Electric field outside conductor?

Answer: Non-zero

Explanation: Due to surface charge.

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140. Gaussian surface nature?

Answer: Imaginary closed surface

Explanation: Mathematical tool.

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141. Flux through cube?

Answer: Same as sphere

Explanation: Shape independent.

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142. Field inside hollow sphere?

Answer: Zero

Explanation: No enclosed charge.

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143. Field outside sphere?

Answer: Like point charge

Explanation: Radial.

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144. Flux through plane?

Answer: Depends on angle

Explanation: Orientation.

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145. Field symmetry types?

Answer: Spherical, cylindrical, planar

Explanation: Common symmetries.

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146. Electric field lines?

Answer: Continuous

Explanation: Do not break.

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147. Field lines start from?

Answer: Positive charge

Explanation: Originate outward.

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148. Field lines end at?

Answer: Negative charge

Explanation: Terminate inward.

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149. Field direction?

Answer: Tangent to field line

Explanation: Direction indicator.

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150. Final summary of Gauss’s Law?

Answer: Flux depends only on enclosed charge

Explanation: Core principle.

151. What is flux through a closed surface enclosing charge Q?

Answer:

$$$$Φ=Qε0

Φ=

ε

0​

Q​

Explanation: From Gauss’s law.

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152. What is flux through closed surface if no charge is inside?

Answer: Zero

Explanation: No enclosed charge.

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153. What is flux through surface if charge is outside?

Answer: Zero

Explanation: Only enclosed charge matters.

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154. What is electric field inside conductor?

Answer: Zero

Explanation: Charges rearrange.

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155. What is electric field at conductor surface?

Answer: Perpendicular

Explanation: No tangential component.

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156. What is Gaussian surface?

Answer: Imaginary closed surface

Explanation: Used in Gauss law.

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157. What is field due to spherical charge outside?

Answer: Like point charge

Explanation: Radial symmetry.

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158. What is field inside hollow sphere?

Answer: Zero

Explanation: No enclosed charge.

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159. What is electric field inside uniformly charged sphere?

Answer: Varies with radius

Explanation: Not constant.

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160. What is flux through cube enclosing charge?

Answer: Same as any surface

Explanation: Shape independent.

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161. What is flux per face of cube (charge at center)?

Answer: 

$\frac{Q}{6{\epsilon }_0}$

Explanation: Equal distribution.

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162. What is electric field direction at surface?

Answer: Normal

Explanation: Perpendicular.

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163. What is flux sign for outward field?

Answer: Positive

Explanation: Leaving surface.

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164. What is flux sign for inward field?

Answer: Negative

Explanation: Entering surface.

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165. What is field inside cavity without charge?

Answer: Zero

Explanation: Shielding.

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166. What is field inside cavity with charge?

Answer: Non-zero

Explanation: Due to internal charge.

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167. What is Gauss law used for?

Answer: Calculating electric field

Explanation: Especially symmetric systems.

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168. What is required for easy Gauss law application?

Answer: Symmetry

Explanation: Simplifies math.

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169. What is electric field lines relation to flux?

Answer: Proportional

Explanation: More lines → more flux.

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170. What is electric field at sharp edges?

Answer: Very high

Explanation: Charge concentration.

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🔹 171–185 (Advanced Concepts)

171. What is electric field inside solid conductor?

Answer: Zero

Explanation: Electrostatic equilibrium.

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172. Where does excess charge reside?

Answer: On surface

Explanation: Due to repulsion.

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173. What is flux independent of?

Answer: Surface shape

Explanation: Only charge matters.

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174. What is flux dependent on?

Answer: Enclosed charge

Explanation: Gauss law.

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175. What is electric field direction for sphere?

Answer: Radial

Explanation: Symmetry.

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176. What is Gaussian surface for plane sheet?

Answer: Pillbox

Explanation: Planar symmetry.

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177. What is Gaussian surface for line charge?

Answer: Cylinder

Explanation: Cylindrical symmetry.

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178. What is Gaussian surface for spherical charge?

Answer: Sphere

Explanation: Radial symmetry.

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179. What is electric field due to infinite plane sheet?

Answer: Constant

Explanation: Independent of distance.

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180. What is electric field due to line charge?

Answer: Decreases with distance

Explanation: 

$\propto \frac{1}{r}$

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181. What is flux through hemisphere?

Answer: Half of sphere

Explanation: Symmetry.

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182. What is electric field inside charged shell?

Answer: Zero

Explanation: No enclosed charge.

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183. What is electric field outside shell?

Answer: Like point charge

Explanation: From center.

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184. What is electric field discontinuity at surface?

Answer: Normal component changes

Explanation: Due to surface charge.

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185. What is tangential component of field at boundary?

Answer: Continuous

Explanation: Does not change.

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🔹 186–200 (Quick Revision)

186. What is normal component of electric field at boundary?

Answer: Discontinuous

Explanation: Depends on charge.

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187. What is flux unit?

Answer: 

$N{m}^2\mathrm{/}C$

Explanation: SI unit.

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188. What is electric field inside conductor?

Answer: Zero

Explanation: Charges cancel field.

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189. What is electric field outside conductor?

Answer: Non-zero

Explanation: Due to surface charge.

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190. What is flux through any closed surface?

Answer: 

$Q\mathrm{/}{\epsilon }_0$

Explanation: Gauss law.

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191. What is electric field lines nature?

Answer: Continuous

Explanation: Do not break.

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192. What is electric field lines start from?

Answer: Positive charge

Explanation: Originate outward.

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193. What is electric field lines end at?

Answer: Negative charge

Explanation: Terminate inward.

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194. What is field direction?

Answer: Tangent to field line

Explanation: Shows direction.

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195. What is flux for uniform field?

Answer: Easy to calculate

Explanation: Constant field.

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196. What is flux if θ = 0°?

Answer: Maximum

Explanation: Cos 0 = 1.

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197. What is flux if θ = 90°?

Answer: Zero

Explanation: Cos 90 = 0.

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198. What is Gauss law importance?

Answer: Simplifies field calculation

Explanation: Powerful tool.

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199. What is flux additive?

Answer: Yes

Explanation: Sum of contributions.

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200. What is final summary of Gauss’s Law?

Answer: Electric flux through closed surface depends only on enclosed charge

Explanation: Fundamental electrostatic principle.