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Correct Answer: C
Correct Answer: C
Method / Topic: Physics
The correct option matches the required rule and the given information.
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Correct Answer: C
Method / Topic: Physics
For capacitor discharge, V(t) = V0e^(−t/RC). At t = RC = τ, V/V0 = e⁻¹ ≈ 0.37, so about 37% remains. The commonly remembered 63% is the fraction of the final voltage gained during charging after one time constant. This result follows from the stated physical model and consistent SI units. For MCAT physics, first identify the system, list known quantities, and choose the governing relationship before substituting numbers. Track direction, signs, exponents, and unit conversions; then test whether the magnitude is physically reasonable. Common distractors omit a round trip, confuse radius with area, ignore an inverse-square or fourth-power dependence, use peak instead of average behavior, or mix stored energy with dissipated power. In clinical and laboratory settings, the same
helps interpret imaging depth, fluid flow, electrical discharge, forces, and energy safely. A final dimensional check should reproduce the unit requested in the
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PASSAGE 3 — DEFIBRILLATOR CIRCUIT A defibrillator stores energy in a 100 μF capacitor charged to 2000 V. It is then discharged through an effective 50 Ω resistance. Use U = ½CV² and the RC time constant τ = RC. Assume the capacitor, resistor, and leads behave ideally for the calculations. QUESTION 9: After one time constant has elapsed during discharge, approximately what percentage of the initial capacitor voltage remains?
Explanation
Correct Answer: C
Method / Topic: Physics
The correct option matches the required rule and the given information.
Short Explanation
Detailed Explanation
Correct Answer: C
Method / Topic: Physics
For capacitor discharge, V(t) = V0e^(−t/RC). At t = RC = τ, V/V0 = e⁻¹ ≈ 0.37, so about 37% remains. The commonly remembered 63% is the fraction of the final voltage gained during charging after one time constant. This result follows from the stated physical model and consistent SI units. For MCAT physics, first identify the system, list known quantities, and choose the governing relationship before substituting numbers. Track direction, signs, exponents, and unit conversions; then test whether the magnitude is physically reasonable. Common distractors omit a round trip, confuse radius with area, ignore an inverse-square or fourth-power dependence, use peak instead of average behavior, or mix stored energy with dissipated power. In clinical and laboratory settings, the same
helps interpret imaging depth, fluid flow, electrical discharge, forces, and energy safely. A final dimensional check should reproduce the unit requested in the
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