Charge quantization: Which unit of electric charge corresponds to approximately 6.25 × 10^18 electrons?

Introduction / Context:
Electric charge is quantized in multiples of the elementary charge carried by electrons and protons. Converting between a count of electrons and standard SI units helps relate microscopic particles to macroscopic measurements.

Given Data / Assumptions:

• Elementary charge magnitude e ≈ 1.602 × 10^-19 coulomb per electron.
• Electron count given as about 6.25 × 10^18.
• Aim is to identify the corresponding SI unit name.

Concept / Approach:
Total charge Q equals number of electrons n multiplied by the elementary charge e, with a negative sign for electrons that is ignored for magnitude. Using approximate values leads to the definition of one coulomb.

Step-by-Step Solution:
Use relation: Q = n * e.Substitute n ≈ 6.25 × 10^18 and e ≈ 1.6 × 10^-19 C.Compute magnitude: Q ≈ (6.25 × 10^18) * (1.6 × 10^-19) C ≈ 1.0 C.Therefore the unit name for this quantity is the coulomb.

Verification / Alternative check:
By definition, 1 coulomb equals approximately 6.242 × 10^18 elementary charges; rounding explains the 6.25 figure commonly used in introductory problems.

Why Other Options Are Wrong:
Ampere: unit of current (charge per second), not charge itself.Volt: unit of electric potential difference.Joule: unit of energy.

Common Pitfalls:
Treating ampere and coulomb interchangeably; they measure different physical quantities.Forgetting the sign of electron charge; here only the magnitude is relevant.

Final Answer:
A coulomb