In a medium,the speed of a light wave decreases to $0.2$ times its speed in free space. The ratio of relative permittivity to the refractive index of the medium is $x: 1$. The value of $x$ is $...........$ (Given: speed of light in free space $= 3 \times 10^8 \ m \ s^{-1}$ and for the given medium $\mu_r = 1$)

  • A
    $5$
  • B
    $4$
  • C
    $3$
  • D
    $2$

Explore More

Similar Questions

$A$ mark at the bottom of a liquid appears to rise by $0.1 \ m$. The depth of the liquid is $1 \ m$. The refractive index of the liquid is

The refractive index of air is $1.0003$. The thickness of an air column that will contain one more wavelength of yellow light $(6000 \mathring A)$ than in the same thickness in a vacuum is:

The refractive index of water is $1.33$. The direction in which a man under water should look to see the setting sun is

Light enters from air into a given medium at an angle of $45^{\circ}$ with the interface of the air-medium surface. After refraction,the light ray is deviated through an angle of $15^{\circ}$ from its original direction. The refractive index of the medium is

Monochromatic light of wavelength $589 \; nm$ is incident from air on a water surface. What are the wavelength,frequency,and speed of
$(a)$ reflected,and
$(b)$ refracted light? Refractive index of water is $1.33$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo