Physics Electrostatics ETEA 2023
PMDC Verified Question 44 of 131
Q.161 Two charges of magnitude \( q_1 = 1\mu\text{C} \) and \( q_2 = 5\mu\text{C} \), are separated at a distance \( r = 1 \times 10^{-3} \text{ m} \) apart, the ratio of the magnitude of the forces acting on them will be:
A
1:5
B
1:25
C
1:3
D
1:1
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: 1:1
1. Concept:

Newton's Third Law of Motion strictly dictates that all forces are mutual interactions. An electrostatic force is a shared bond between two objects.

2. Formula:

$$ F_1 = F_2 = k \frac{q_1 q_2}{r^2} $$

3. Solution:

  • Despite \( q_2 \) being five times larger in magnitude than \( q_1 \), the actual force formula multiplies them together.


  • The force \( q_1 \) feels is \( k(1)(5)/r^2 \).


  • The force \( q_2 \) feels is \( k(5)(1)/r^2 \).


  • Both forces are mathematically identical, making their ratio perfectly 1:1.


4. Why other options are incorrect:

Option A attempts to bait students into comparing the ratio of the charges themselves, rather than the mutual forces they experience.

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.

Previous Question All Electrostatics MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App