Introduction

Electric charge is one of the fundamental properties of matter that gives rise to electric forces and electric fields. Every particle in the universe is either positively charged, negatively charged, or neutral. The concept of electric charge is the foundation of electrostatics, electricity, and electromagnetism, which are crucial branches of physics.

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What is Electric Charge?

• Electric charge is a physical property of matter that causes it to experience a force when placed in an electric or magnetic field.
• There are two types of charges:
  1. Positive Charge (+) – carried by protons
  2. Negative Charge (–) – carried by electrons
• A body with equal number of protons and electrons is neutral.

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Properties of Electric Charge

• Charges are quantized → smallest unit is the charge of an electron (e = 1.6 × 10⁻¹⁹ C).
• Charges are additive.
• Charges are conserved → cannot be created or destroyed.
• Like charges repel; unlike charges attract.

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Unit of Electric Charge

• SI Unit: Coulomb (C)
• 1 Coulomb = charge of 6.25 × 10¹⁸ electrons.

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Laws of Electric Charges

1. Coulomb’s Law: The electrostatic force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
2. Law of Conservation of Charge: Total charge in an isolated system always remains constant.

Electric Charges And Fields Complete Notes

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Interesting Facts about Electric Charges

• A lightning bolt contains about 5 coulombs of charge and can reach up to 30,000 amperes.
• Amber rubbed with fur was the first observation of electric charge (by the Greeks around 600 BC).
• Earth itself carries a net negative charge.
• Human body produces small electric charges that are essential for nerve impulses and heartbeat.
• Electric charges move through metals because of free electrons.

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Applications of Electric Charge

• Electrostatics: Photocopiers, laser printers, and painting cars.
• Electronics: Current flow in circuits depends on movement of charges.
• Medical field: ECG, EEG work on electric signals.
• Daily life: Static electricity in clothes, balloons, lightning.

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100 GK Questions on Electric Charges

Basics of Electric Charge

1. Who first observed electric charges? – Thales of Miletus
2. What are the two types of electric charges? – Positive and Negative
3. Which particle carries negative charge? – Electron
4. Which particle carries positive charge? – Proton
5. What is the SI unit of electric charge? – Coulomb (C)
6. What is the charge of an electron? – –1.6 × 10⁻¹⁹ C
7. What is the charge of a proton? – +1.6 × 10⁻¹⁹ C
8. A body with equal protons and electrons is called – Neutral
9. What is the symbol of charge? – q
10. What is the smallest unit of charge? – Elementary charge (e)

Electric Charges And Fields Complete Notes

Properties of Charges

11. Like charges – Repel each other
12. Unlike charges – Attract each other
13. Which law states force between charges? – Coulomb’s law
14. Electric charge is always – Conserved
15. Electric charge is – Quantized
16. The additive property of charges means – Algebraic sum of charges
17. Earth has which type of charge? – Negative
18. In metals, current flows due to – Free electrons
19. In electrolytes, current flows due to – Ions
20. SI unit of current derived from charge? – Ampere

स्थिर वैद्युत आवेश एवं क्षेत्र सम्पूर्ण नोट्स

Coulomb’s Law

21. Formula of Coulomb’s law – F = k q₁q₂ / r²
22. Coulomb’s constant k = – 9 × 10⁹ Nm²/C²
23. Force between two like charges is – Repulsive
24. Force between two unlike charges is – Attractive
25. If distance doubles, force becomes – One-fourth

Measurement & Detection

26. Instrument to detect charge – Electroscope
27. Instrument to measure small charge – Electrometer
28. Lightning is a natural example of – Electric discharge
29. Which law is used in electroscope? – Law of electrostatics
30. SI unit of electric field – Newton per coulomb (N/C)

Static Electricity

31. Rubbing amber with fur produces – Static electricity
32. Static electricity is stronger in – Dry weather
33. Static charge is measured in – Coulombs
34. Device for storing charges – Capacitor
35. Leyden jar is used to – Store electric charge

Interesting Facts

36. Lightning contains about – 5 Coulombs of charge
37. Lightning current can reach – 30,000 amperes
38. Human body produces charges for – Nerve impulses
39. Electric fish like eel generate – Electric charges
40. A photocopier works on – Electrostatics

Discoveries & Scientists

41. Who discovered Coulomb’s law? – Charles-Augustin de Coulomb
42. Who invented the electroscope? – William Gilbert
43. SI unit of charge is named after – Coulomb
44. Discovery of electron – J.J. Thomson
45. Discovery of proton – Goldstein

Applications of Charge

46. Car painting uses – Electrostatic spraying
47. Laser printer works on – Electrostatics
48. Photocopier machine works on – Electric charges
49. ECG measures – Electric signals in heart
50. EEG measures – Electric signals in brain

Advanced GK

51. What is the permittivity of free space (ε₀)? – 8.85 × 10⁻¹² C²/Nm²
52. Coulomb’s law is similar to – Newton’s law of gravitation
53. Unit of electric flux – Newton meter² per coulomb (Nm²/C)
54. Force between charges in vacuum is – Maximum
55. Charges on conductors reside on – Outer surface

Everyday Life Examples

56. When clothes stick after washing – Static charge
57. Balloon sticks to wall due to – Electrostatic force
58. Shock while touching door handle – Static discharge
59. Lightning rod protects from – Electric charge buildup
60. Dust removal from air uses – Electrostatic precipitator

Charge & Particles

61. Which particle is charge carrier in metals? – Electrons
62. Which particle is charge carrier in semiconductors? – Electrons and holes
63. Neutron carries – No charge
64. Proton is heavier than – Electron
65. Charge of alpha particle – +2e

More Interesting Facts

66. One Coulomb = charge of – 6.25 × 10¹⁸ electrons
67. Charge of quark – Fractional charge (±1/3, ±2/3 e)
68. Electric field around a point charge is – Radial
69. Electric field inside a conductor – Zero
70. Lightning travels at – One-third speed of light

Historical GK

71. Word “Electricity” derived from – Greek word Elektron (Amber)
72. Benjamin Franklin proposed – Positive and negative charges
73. William Gilbert is known as – Father of Electricity
74. Michael Faraday contributed to – Electromagnetism
75. James Clerk Maxwell formulated – Electromagnetic theory

Quick Facts GK

76. Charge is a – Scalar quantity
77. Current is – Rate of flow of charge
78. 1 Ampere = 1 Coulomb/second
79. Electrostatics deals with – Stationary charges
80. Electrodynamics deals with – Moving charges

Competitive GK

81. Charge on positron – +e
82. Which particle has equal mass to electron but opposite charge? – Positron
83. Lightning lasts for – Few microseconds
84. Electric charge produces – Electric field
85. Changing charge produces – Electric current

Everyday Phenomena

86. Photocopy machine uses – Xerography
87. Spray painting uses – Electrostatics
88. Television screen attracts dust due to – Static charge
89. Inkjet printers work on – Electric charges
90. Van de Graaff generator is used to – Generate high voltage

Final 10 Quick Q&A

91. Charge of beta particle – –e
92. Which particle is neutral? – Neutron
93. Charge conservation means – Total charge remains constant
94. Who coined the term “electron”? – George Johnstone Stoney
95. Which scientist flew a kite to study lightning? – Benjamin Franklin
96. Dry hair attracts comb due to – Static charge
97. Photographic plates use – Electric charges
98. Capacitors store – Electric charge and energy
99. Net charge of an atom is – Zero (neutral)
100. Lightning safety device on buildings – Lightning conductor

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