Physics Electrostatics DUHS 2022
PMDC Verified Question 80 of 131
Q.140 If \( 2\mu\text{F} \) and \( 4\mu\text{F} \) capacitors are connected in series. Their equivalent capacitance will be:
A
\( 8 \mu\text{F} \)
B
\( 0.75 \mu\text{F} \)
C
\( 1.33 \mu\text{F} \)
D
\( 6 \mu\text{F} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \( 1.33 \mu\text{F} \)
1. Concept:

When capacitors are linked in series, their combined effective plate distance effectively increases, which reduces the total capacitance. We use the reciprocal sum rule.

2. Formula:

$$ C_{eq} = \frac{C_1 \times C_2}{C_1 + C_2} $$

3. Solution:

  • Identify the values: \( C_1 = 2 \mu\text{F} \) and \( C_2 = 4 \mu\text{F} \).


  • Multiply them for the numerator: \( 2 \times 4 = 8 \).


  • Add them for the denominator: \( 2 + 4 = 6 \).


  • Divide: \( C_{eq} = 8 / 6 = 1.33 \mu\text{F} \).


4. Why other options are incorrect:

Option D (6) is the answer if they were connected in parallel (simply adding them). Option B (0.75) is the inverted result (6/8), common if a student forgets to flip the final reciprocal fraction.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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