In basic electrical engineering, what is the SI unit used to quantify electric charge? Choose the most appropriate fundamental unit.

Introduction / Context:
Understanding the correct SI units is essential for solving any electrical or electronics problem. Electric charge is the foundational quantity from which current, voltage relationships, and many circuit behaviors are derived. This question checks whether you can identify the standard SI unit for charge.

Given Data / Assumptions:

• The question asks specifically for the SI (International System of Units) unit of electric charge.
• Only one option is the correct SI base-derived unit for this quantity.
• Other options represent different electrical or power-related quantities, not charge.

Concept / Approach:

The SI unit of electric charge is the coulomb, symbol C. One coulomb corresponds to the quantity of electricity transported by a steady current of one ampere flowing for one second. Thus, 1 C = 1 A * s. While 'ampere-second' is dimensionally equivalent, the accepted SI name for the unit of charge is 'coulomb' and should be preferred in scientific communication and standards.

Step-by-Step Solution:

Verification / Alternative check:

From current definition I = Q / t, rearrange to Q = I * t. If I is in amperes and t in seconds, Q is in coulombs. This validates that the standard unit name for charge is the coulomb, not volt, watt, or joule.

Why Other Options Are Wrong:

Joule measures energy, volt measures electric potential difference, and watt measures power. 'Ampere-second' is dimensionally correct but not the SI unit name; the accepted term is coulomb.

Common Pitfalls:

Confusing energy (joule) and charge (coulomb), or thinking volt (potential) represents quantity of charge. Also writing units as 'ampere-second' instead of using the standard name 'coulomb' in final answers.

Final Answer:

coulomb