Physics Electrostatics KU 2024
PMDC Verified Question 11 of 131
Q.188 Two points charges, \( +5\mu\text{C} \) and \( -5\mu\text{C} \) are placed at points A and B, respectively, which are separated by a distance 2d. What is the electric potential at the midpoint M of the line joining A and B?
A
\( 2kQ/d \)
B
\( kQ/d \)
C
\( -kQ/d \)
D
Zero
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

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

This setup describes a classic electric dipole. Electric potential is a scalar quantity, meaning the potentials from multiple charges simply add algebraically (keeping their positive or negative signs).

2. Formula:

$$ V_{net} = V_+ + V_- $$

3. Solution:

  • The total distance is \( 2d \), meaning the midpoint M is exactly distance \( d \) away from both charges.


  • Potential from positive charge: \( V_+ = \frac{k(+5\mu\text{C})}{d} \).


  • Potential from negative charge: \( V_- = \frac{k(-5\mu\text{C})}{d} \).


  • Summing them: \( V_{net} = \frac{k(5\mu\text{C})}{d} - \frac{k(5\mu\text{C})}{d} = 0 \).


4. Why other options are incorrect:

Options A, B, and C would apply if the question asked for Electric Field intensity (a vector, where the two fields would point in the exact same direction and constructively add together). Potential, being scalar, strictly cancels.

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