A body is charged negatively. It implies that

1. Fundamental Structure of the Atom (basic)

To understand electricity, we must first look at the smallest unit of matter: the atom. An atom is the smallest particle of an element that retains its unique characteristics Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Major Crops and Cropping Patterns in India, p.100. At its heart lies the atomic nucleus, a small, dense, positively charged central portion containing protons (which carry a positive charge) and neutrons (which are neutral). Swirling around this nucleus in various energy levels or shells are the electrons, which carry a negative charge.

In a stable, neutral state, an atom has an equal number of protons and electrons, meaning the positive and negative charges perfectly cancel each other out. However, these particles are not held with equal strength. While protons are tightly bound within the nucleus and do not move during ordinary physical or chemical interactions, electrons—especially those in the outermost shells—are labile. This means they can be transferred from one atom to another through processes like friction, contact, or chemical reactions Science, class X (NCERT 2025 ed.), Metals and Non-metals, p.46.

When this balance of charges is disrupted, the atom becomes an ion. If an atom loses an electron, it is left with more protons than electrons, resulting in a net positive charge called a cation (e.g., Na⁺). Conversely, if an atom gains an extra electron from an outside source, the excess negative charge turns it into an anion Science, class X (NCERT 2025 ed.), Metals and Non-metals, p.46. Understanding this mobility of electrons is crucial because the movement of these negative charges is exactly what constitutes an electric current.

Particle	Charge	Location	Mobility
Proton	Positive (+)	Nucleus	Fixed / Stationary
Electron	Negative (-)	Outer Shells	Mobile / Labile
Neutron	Neutral (0)	Nucleus	Fixed / Stationary

Sources: Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Major Crops and Cropping Patterns in India, p.100; Science, class X (NCERT 2025 ed.), Metals and Non-metals, p.46; Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.), Chapter 25: Thunderstorm, p.348

2. Properties of Electric Charge (basic)

To understand electricity, we must first look at the intrinsic property of matter called electric charge. At its most fundamental level, an atom consists of a central nucleus containing protons (positive charge) and a surrounding cloud of electrons (negative charge). In a neutral state, these charges balance out perfectly. However, electricity is fundamentally about the movement of these charges. Specifically, it is the electrons that are the 'travelers' of the atomic world. Because protons are tightly bound within the nucleus by strong nuclear forces, they do not move during ordinary physical processes like friction or contact Physical Geography by PMF IAS, Chapter 25: Thunderstorm, p. 348. When we say an object has become negatively charged, we mean it has acquired an excess of electrons from another source. Conversely, a positively charged body is one that has lost electrons. It is a common misconception to think a body becomes positive by gaining protons; in reality, it simply has a 'deficit' of electrons, leaving the existing protons' positive charge 'unmasked.' This movement of charge is what allows for the flow of electric current, which we measure as the amount of charge flowing through a particular area in unit time Science, class X (NCERT 2025 ed.), Electricity, p.172. Two critical properties of charge to remember are Conservation and Quantization:

• Conservation of Charge: The total charge of an isolated system remains constant. Charge is neither created nor destroyed; it is only transferred from one body to another.
• Quantization of Charge: Charge exists in discrete 'packets.' The total charge (Q) on a body is always an integral multiple of the basic unit of charge (e), which is the charge of a single electron (approximately 1.6 × 10⁻¹⁹ C). We express this as Q = ne.

In practical circuits, we often measure the work done (W) to move a unit charge (Q) between two points, which defines the electric potential difference (V). This relationship is expressed as V = W/Q, where the SI unit of potential difference is the Volt (V) Science, class X (NCERT 2025 ed.), Electricity, p.173.

Sources: Physical Geography by PMF IAS, Chapter 25: Thunderstorm, p.348; Science, class X (NCERT 2025 ed.), Electricity, p.172; Science, class X (NCERT 2025 ed.), Electricity, p.173

3. Conductors, Insulators, and Semiconductors (intermediate)

To understand electricity, we must first understand why some materials allow it to flow while others block it entirely. At the atomic level, electric current is essentially the flow of electrons. In a conductor, electrons are not tightly bound to their parent atoms; they are relatively free to move through the material. Metals are classic examples of conductors because they can easily lose electrons to form positive ions, creating a "sea" of mobile charge carriers (Science Class X, Metals and Non-metals, p.55). While silver and copper are the most efficient conductors, copper is the standard choice for household wiring because it balances high conductivity with affordability (Science Class VII, Electricity: Circuits and their Components, p.36).

On the opposite end of the spectrum are insulators. These materials, such as rubber, plastic, and ceramics, offer extremely high resistance to the flow of electrons. In an insulator, electrons are held tightly by their atoms and cannot move freely. This property is just as vital as conductivity; insulators are used to coat electrical wires and switches to protect us from electric shocks by preventing current from escaping the intended path (Science Class VII, Electricity: Circuits and their Components, p.36). A material that offers some resistance but still allows flow is often called a resistor, which helps control the amount of current in a circuit (Science Class X, Electricity, p.177).

Finally, we have semiconductors (like silicon and germanium). These are "intermediate" materials—they don't conduct as well as metals, but they aren't quite insulators either. Their unique ability is that their conductivity can be changed by adding impurities or changing their temperature. This "tunable" nature is what makes them the backbone of all modern electronics, from your smartphone to the computer chips in a car.

Material Type	Electron Mobility	Resistance Level	Common Examples
Conductor	High (Free to move)	Very Low	Silver, Copper, Aluminum
Insulator	Negligible (Tightly bound)	Extremely High	Rubber, Glass, Plastic
Semiconductor	Moderate/Controllable	Intermediate	Silicon, Germanium

Sources: Science Class X, Metals and Non-metals, p.55; Science Class VII, Electricity: Circuits and their Components, p.36; Science Class X, Electricity, p.177

4. Atmospheric Electricity: Lightning and Thunder (intermediate)

To understand lightning, we must first look at the massive "battery" created in the sky: the cumulonimbus cloud. These clouds are unique because of their extensive vertical development, which allows for intense internal activity Physical Geography by PMF IAS, Hydrological Cycle (Water Cycle), p.335. Within these clouds, vigorous updrafts of warm air and downdrafts of cold precipitation cause particles to collide at high speeds. This constant rubbing and friction lead to the development of static electric charges.

Through these collisions, a process of charge separation occurs. The lighter ice particles usually gain a positive charge and are carried by updrafts to the upper reaches of the cloud. Conversely, heavier elements like hail and large water droplets acquire a negative charge and settle in the lower part of the cloud Science, Class VIII, NCERT (Revised ed 2025), Pressure, Winds, Storms, and Cyclones, p.91. It is important to remember that this negative charge is the result of an excess of electrons; while protons remain fixed in the atomic nuclei, electrons are mobile and are transferred during these high-energy collisions.

Cloud Region	Predominant Charge	Particle Type
Upper Cloud	Positive (+)	Lighter ice crystals
Lower Cloud	Negative (–)	Heavier water droplets/hail

As the negative charge at the cloud's base intensifies, it induces a positive charge on the ground below—on trees, buildings, and even people. Air usually acts as an insulator, preventing electricity from flowing between the cloud and the ground. However, when the electrical potential difference becomes overwhelming, the air "breaks down" and becomes a conductor. A sudden, massive flow of electrons occurs—this is lightning. The surrounding air is instantly heated to temperatures five times hotter than the sun's surface, causing it to expand explosively. This rapid expansion creates a sonic shockwave that we hear as thunder.

Sources: Physical Geography by PMF IAS, Hydrological Cycle (Water Cycle), p.335; Science, Class VIII, NCERT (Revised ed 2025), Pressure, Winds, Storms, and Cyclones, p.91; Physical Geography by PMF IAS, Thunderstorm, p.344; Physical Geography by PMF IAS, Thunderstorm, p.350

5. Methods of Charging: Friction, Conduction, and Induction (exam-level)

To understand how objects become charged, we must first look at the atom. An atom consists of a nucleus containing protons and neutrons, with electrons orbiting around it. In ordinary physical processes, protons are tightly bound within the nucleus and do not move; therefore, charging is entirely about the movement of electrons. When a body gains electrons, it becomes negatively charged; when it loses them, it becomes positively charged Physical Geography by PMF IAS, Chapter 25, p.348.

There are three primary methods by which this electron transfer or redistribution occurs:

• Friction (Charging by Rubbing): When two different materials are rubbed together, the friction provides enough energy to knock electrons off one material and transfer them to the other. For instance, if you rub a balloon with a woolen cloth, the balloon and the cloth acquire opposite charges and will subsequently attract each other Science, Class VIII, Exploring Forces, p.71. These are often called static charges because they remain on the object's surface without moving through a circuit Science, Class VIII, Exploring Forces, p.70.
• Conduction (Charging by Contact): This occurs when a charged object physically touches a neutral conductor. If a negatively charged rod touches a neutral metal sphere, some excess electrons flow directly onto the sphere. In conduction, the neutral object always acquires the same sign of charge as the charging body.
• Induction (Charging without Contact): This is a sophisticated method where a charged object is brought near (but not touching) a neutral conductor. The electric field of the charged object causes the internal charges of the neutral body to redistribute—opposite charges are pulled closer, while like charges are pushed away. If the neutral body is briefly "grounded" (connected to the Earth) while the charged object is still nearby, it can acquire a permanent opposite charge.

The following table summarizes these interactions for quick revision:

Method	Physical Contact?	Resulting Charge on Neutral Body
Friction	Yes (Rubbing)	Opposite to the other object
Conduction	Yes (Touching)	Same as the charging object
Induction	No (Nearby)	Opposite (if grounded) or Redistribution

Sources: Physical Geography by PMF IAS, Chapter 25: Thunderstorm, p.348; Science, Class VIII (NCERT), Exploring Forces, p.70; Science, Class VIII (NCERT), Exploring Forces, p.71

6. Electronic Theory of Electrification (exam-level)

To understand the Electronic Theory of Electrification, we must first look at the architecture of an atom. In its normal state, an atom is electrically neutral because it contains an equal number of protons (positively charged) in its nucleus and electrons (negatively charged) orbiting that nucleus. Electrification is the process by which this balance is disrupted, turning a neutral body into a charged one.

The core principle of this theory is that electrons are mobile, while protons are stationary. Protons are held tightly within the nucleus by immense nuclear forces and do not move during ordinary physical processes like friction or contact. Electrons, however—especially those in the outermost or valence shell—are relatively labile. They can be transferred from one object to another through rubbing (friction), conduction, or induction. When two bodies are rubbed together, the material with a weaker hold on its electrons loses them to the other material. This results in an anion (a negatively charged body with excess electrons) and a cation (a positively charged body with a deficit of electrons) Physical Geography by PMF IAS, Thunderstorm, p.348.

For instance, consider the formation of ions in chemistry. If a sodium atom loses an electron, it still has 11 protons but only 10 electrons, resulting in a net positive charge (Na⁺). Conversely, an element like chlorine seeks to gain an electron to complete its outer shell; by doing so, it acquires more negative charge than positive, becoming an anion (Cl⁻) Science, Class X (NCERT 2025 ed.), Metals and Non-metals, p.46. This same principle applies on a larger scale in nature, such as in lightning, where collisions within clouds cause a massive separation of charges, leading to the top of the cloud becoming positively charged while the base becomes negatively charged Physical Geography by PMF IAS, Thunderstorm, p.348.

State	Electron Count	Net Charge	Scientific Term
Neutral	Equal to Protons	Zero	Atom/Molecule
Negative	Greater than Protons	Negative (–)	Anion
Positive	Less than Protons	Positive (+)	Cation

Sources: Physical Geography by PMF IAS, Thunderstorm, p.348; Science, Class X (NCERT 2025 ed.), Metals and Non-metals, p.46

7. Solving the Original PYQ (exam-level)

Now that you have mastered the basics of atomic structure and electrostatics, you can see how those building blocks directly solve this PYQ. In your previous lessons, we established that atoms are composed of a central nucleus and orbiting electrons. The fundamental rule to remember is that while protons (positive) are held tightly within the nucleus by strong nuclear forces, electrons (negative) are mobile charge carriers. This means that in any ordinary physical interaction or charging process, it is the movement of electrons—not protons—that dictates the net charge of an object.

To arrive at the correct answer, think of a neutral body as a scale in perfect balance between positive and negative charges. To make the body negatively charged, you must add more "negative weight" to that scale. Since protons cannot be easily moved or removed, the only way to achieve this imbalance is if the body acquired some electrons from outside. As noted in Physical Geography by PMF IAS, this transfer of electrons is exactly what happens during physical processes like friction or contact, leading to an accumulation of negative charge.

UPSC often uses options like (A) and (C) as traps to test your conceptual clarity. Option (A) is a common distractor; losing protons would indeed change the charge balance, but it is physically impossible during standard charging because it would require a nuclear reaction. Option (C) is the opposite of what we need—losing electrons would leave an excess of protons, making the body positively charged. Therefore, by focusing on the mobility of electrons and the stability of the nucleus, you can clearly identify (B) as the only scientifically sound conclusion.