Electrostatics and units: one coulomb of charge corresponds to approximately how many elementary charges (electrons) in magnitude?

Introduction / Context:
Electrical charge is quantized in units of the elementary charge e. Relating the SI unit coulomb (C) to the number of electrons builds intuition for circuit analysis, capacitor charge storage, and semiconductor doping levels.

Given Data / Assumptions:

• Elementary charge magnitude: e ≈ 1.602 × 10^-19 C.
• One coulomb is the total charge carried by many electrons.
• We seek a count of electrons whose total charge magnitude equals 1 C.

Concept / Approach:
Use the proportionality: total charge Q equals number of electrons n times elementary charge e in magnitude. That is Q = n * e. Solve for n = Q / e with Q = 1 C and e = 1.602 × 10^-19 C.

Step-by-Step Solution:
Write relation: n = Q / e.Substitute values: n = 1 / (1.602 × 10^-19).Compute order of magnitude: n ≈ 6.24 × 10^18 electrons.

Verification / Alternative check:
Check units: coulomb divided by coulomb per electron leaves a pure count. The value 6.24 × 10^18 is the standard rounded figure used in textbooks and exam tables.

Why Other Options Are Wrong:
6.24 × 10^-18: inverted exponent, many orders too small.
One ampere or one second: those are current and time units, not counts of charge carriers.

Common Pitfalls:
Mixing sign with magnitude; here we compare magnitudes, so we ignore the negative sign on electron charge. Confusing coulomb (charge) with ampere (charge per second).

Final Answer:
6.24 × 10^18 electrons