Question bank — Electric charge — properties, quantization, conservation

False — a negatively charged body has more electrons than protons; only a positive body has fewer. "Charged" just means the counts don't match, either way.

True — additivity means $(+q)+(-q)=0$, where $q$ is just the shared magnitude. The system as a whole is neutral even though each piece is charged.

False — only the total of the isolated system is fixed. Individual objects freely swap charge (that is exactly what touching conductors do — see figure 2).

False — you can only move whole electrons, so transferred charge is always $ne$ with $n$ an integer. Half an electron is not a thing you can hand over.

False — it separates existing charge by transferring electrons from glass to silk. Glass ends up positive, silk negative; nothing is created (see Methods of Charging).

False — it contains equal amounts of positive and negative charge that cancel in the total. "Neutral" means balanced, not empty.

False — quarks are confined and never observed alone. Any free, isolatable particle carries an integer multiple of $e$, so the free-charge brick stays $e$.

False — charge is a signed scalar; the force gets its direction from the geometry of where charges sit, not from charge itself (see Coulomb's Law).

False for vacuum — charge balances ($0\to (-e)+(+e)$), but energy and momentum cannot both be conserved unless a nearby nucleus absorbs recoil. It needs matter present (figure 1).

Protons are locked in nuclei and don't move in ordinary processes. You make a rod positive by removing electrons, exposing the protons already there.

Nothing was destroyed. Total was $+8\text{C}$ before and $+8\text{C}$ after ($+4$ each); sharing redistributes, it does not delete.

Induction rearranges the object's own charge (or grounds part of it away); no charge jumps across the gap without contact. Total of the isolated set-up is still conserved.

$4.8\times 10^{-19}/1.6\times 10^{-19}=3$, not $2.5$ — so it is actually $3e$ and perfectly allowed. A genuine non-integer would be forbidden by quantization, but this one is integer.

It sits alongside energy and momentum as a fundamental Conservation Laws in Physics result, tied to a deep symmetry — not a one-off electrical convenience.

The charge flows into the Earth, an enormous reservoir; it is relocated, not destroyed. The Earth-plus-conductor total is unchanged.

One type could only ever attract (like mass in gravity). Two signs are needed so that like charges repel and unlike charges attract, matching experiment.

The brick $e\approx 1.6\times 10^{-19}\text{C}$ is so tiny that a $1\text{C}$ charge is $\sim 6.24\times 10^{18}$ electrons; the step between $n$ and $n+1$ looks smooth, like sand looking like fluid from afar.

Charge has magnitude and a $\pm$ sign but no direction, so it is a scalar. A $+2\text{C}$ and a $-2\text{C}$ give $0$, not $4$.

A lone photon converting to two particles cannot conserve energy and momentum simultaneously; a massive third body absorbs the recoil momentum so both are satisfied while charge stays balanced at zero.

For any conductor the charge it holds is $q=CV$, so its potential is $V=q/C$, where $C$ (its capacitance) depends only on size and shape. Identical spheres have identical $C$; on contact they must reach one common $V$, and $q=CV$ with equal $C$ and equal $V$ forces equal $q$ — hence the total splits in half.

Yes — a neutral system can hold separated $+$ and $-$ regions (a dipole) whose parts still push and pull each other; net charge zero, internal forces nonzero.

Yes — $q=0\cdot e=0$ is the $n=0$ case. Quantization allows zero; neutral is just the integer multiple with $n=0$.

No practical limit from charge law itself, but eventually the field gets strong enough to pull charge back (sparking/breakdown), so a real ball caps out physically, not because $q=ne$ forbids it.

No — total is $+5e$, and $+5e/2=+2.5e$ is not an integer multiple of $e$. In practice a real conductor holds billions of bricks, so the sharing is only ever off by at most one whole electron: the two spheres settle at $+3e$ and $+2e$ (or the reverse), with that single leftover brick sitting on one sphere — a difference far too small to measure at macroscopic scales.

Yes — a neutron ($0$) decays to a proton ($+e$), an electron ($-e$), and an antineutrino ($0$); total charge before and after is $0$. The bookkeeping balances exactly (see Atomic Structure).