Fundamental SI quantities in electronics Select the physical quantity measured in joules (J), the SI unit commonly encountered in energy storage, work, and heat calculations.

Introduction / Context:
Units anchor equations to physical meaning. In electronics, the joule appears in capacitor energy (E = 0.5 * C * V^2), inductor energy (E = 0.5 * L * I^2), resistive heating (E = P * t), and battery capacity measurements (watt-hours converted to joules). Knowing what the joule measures prevents dimensional mistakes in design and analysis.

Given Data / Assumptions:

• We seek the physical quantity corresponding to the SI unit joule (J).
• Other options list common but different SI units.
• No special conditions; standard SI definitions apply.

Concept / Approach:
The joule is the SI unit of energy (and work). One joule equals one newton-meter, which also equals one watt-second because power in watts multiplied by time in seconds yields energy in joules. In electrical terms, 1 J = 1 V * 1 C (one volt times one coulomb), reinforcing its connection to stored or transferred energy.

Step-by-Step Solution:

Verification / Alternative check:
Dimensional analysis: volts × coulombs = joules. Since V = J/C by definition, the product returns joules consistently in circuit energy computations.

Why Other Options Are Wrong:

Common Pitfalls:
Mixing energy (J) with power (W); reporting battery capacity only in mAh and forgetting that energy depends on voltage (Wh → J via 1 Wh = 3600 J).

Final Answer:
energy