The velocity of light in a medium depends on

The correct answer is Option (1) → electric and magnetic properties of the medium

The speed of an electromagnetic wave in a medium is set by both the permeability \( \mu \) (magnetic property) and the permittivity \( \varepsilon \) (electric property) of the medium.

    \( \displaystyle v = \frac{1}{\sqrt{\mu\,\varepsilon}} = \frac{c}{\sqrt{\mu_r\,\varepsilon_r}} \)

NCERT (2026-27):
Summary – “… The speed of light, or of electromagnetic waves in a material medium is given by

    \( \displaystyle v = \frac{1}{\sqrt{\mu\,\epsilon}} \)

where μ is the permeability of the medium and ε its permittivity.”