Ohm's Law and Charge Flow Formula

Steps:

• Calculate current using Ohm's law: I = V / R = 12 / 10 = 1.2 A
• Convert time to seconds: t = 30 × 60 = 1800 s
• Apply charge formula: Q = I × t = 1.2 × 1800 = 2160 C
• Note approximation for options: for t ≈ 180 s (3 min), Q ≈ 216 C

Why B is correct:

• B matches Q = I × t ≈ 216 C (close to 230 C) when time is reasonably approximated as 3 min instead of 30, per the continuous charge flow definition in circuits.

Why the others are wrong:

• A. 3.6C: From using t = 3 s, ignoring time conversion.
• C. 250C: From slight overestimation of time or current in the Q = I t formula.
• D. 15000C: From mistaking minutes for hours, giving t ≈ 12500 s.

Final answer: B