Physics Electrostatics UHS 2022
PMDC Verified Question 65 of 131
Q.125 The Coulomb's constant k depends upon?
A
Nature of medium
B
System of units
C
Types of charge
D
Nature of medium and system of units
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Nature of medium and system of units
1. Concept:

Coulomb's constant \( k \) is not a true universal constant like \( c \) (speed of light). Its numerical output relies entirely on the intervening environment and how humans choose to measure it.

2. Formula:

$$ k = \frac{1}{4 \pi \epsilon} $$

3. Solution:

  • The permittivity term (\( \epsilon \)) is dictated by the physical nature of the medium (vacuum vs water vs air).


  • The value of \( k \) changes if measured in SI units (\( 9 \times 10^9 \)) versus CGS units (where \( k \) equals exactly 1). Thus, it heavily depends on the system of units.


4. Why other options are incorrect:

A and B are incomplete on their own. Option C is false because the constant behaves identically regardless of whether the charges are positive or negative.

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