Physics Electrostatics NUMS 2020
PMDC Verified Question 100 of 131
Q.113 If we double the separation between two charges, then coulomb's force will become?
A
Doubled
B
Half
C
4-times
D
\( 1/4^{\text{th}} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: \( 1/4^{\text{th}} \)
1. Concept:

Electrostatic force adheres strictly to the inverse square law; force drops dramatically as objects move apart.

2. Formula:

$$ F \propto \frac{1}{r^2} $$

3. Solution:

  • Let the new separation \( r' = 2r \).


  • Insert this into the denominator: \( (2r)^2 = 4r^2 \).


  • The 4 remains in the denominator, meaning the new overall force is exactly \( 1/4 \) of the original value.


4. Why other options are incorrect:

Option B occurs if force were inversely linear (\( 1/r \)). Option C occurs if you halved the distance rather than doubled it.

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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