Physics Electrostatics SZABMU 2024
PMDC Verified Question 1 of 131
Q.178 The electric flash attachment to a camera contains a capacitor for storing the energy used to produce the flash. In one such unit, the potential difference between the plates of 20 F capacitor is 5 V. Calculate the energy that is used to produce the flash?
A
250 J
B
310 J
C
500 J
D
650 J
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 250 J
1. Concept:

The total electrical potential energy stored in a charged capacitor can be found using its static capacitance and the applied voltage.

2. Formula:

$$ U = \frac{1}{2} C V^2 $$

3. Solution:

  • Given capacitance: \( C = 20 \text{ F} \).


  • Given voltage: \( V = 5 \text{ V} \).


  • Square the voltage: \( 5^2 = 25 \).


  • Substitute values: \( U = \frac{1}{2} (20) (25) \).


  • Calculate: \( U = 10 \times 25 = 250 \text{ J} \).


4. Why other options are incorrect:

Option C (500 J) happens if you forget to include the \( \frac{1}{2} \) coefficient in the energy formula. Options B and D are arbitrary distractors.

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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