Question

Which of the following statements is true for Coulomb's law constant $\left(k\right)$?

• A. For air, $k=9\times {10}^9{\text{N m}}^2{\text{C}}^{-2}$
• B. It is can't be determined when the medium is nitrogen gas
• C. $k$ does not depend on the medium
• D. It is also called vacuum permittivity

Answer 1

The correct option is A For air, $k=9\times {10}^9{\text{N m}}^2{\text{C}}^{-2}$

The symbol $k$ is a proportionality constant known as the Coulomb's law constant. The value of this constant is dependent upon the medium that the charged objects are immersed in. In the case of air, the value is approximately $9\times {10}^9{\text{N m}}^2{\text{C}}^{-2}$.