Coulomb as Unit of Electric Charge Steps:

• Recall the SI definition: 1 coulomb (C) is the charge quantity equal to 1 ampere (A) of current flowing for 1 second (s), from Q = I × t.
• Evaluate choices by matching to this formula, where charge passes a point in 1 s.
• Eliminate options involving energy (joules), power (watts), or resistance (ohms), as they don't define charge directly.
• Identify the option stating exactly 1 A current in 1 s as the match.

Why B is correct:

• It directly matches the definition: Q = 1 A × 1 s = 1 C, the standard SI unit for electric charge.

Why the others are wrong:

• A: Involves work (1 J), which relates to energy (W = QV), not the charge definition.
• C: Power (1 W) is P = IV, requiring unspecified voltage to link to current, not a direct charge definition.
• D: Resistance (1 Ω) from V = IR doesn't define charge quantity.

Final answer: B