Question

The angle of incidence of the electric field (the angle between the field direction and the surface normal) at a plane dielectric boundary outside the dielectric is ( 20^{circ} ). Find the angle of refraction within the medium if the dielectric constant of the medium is 1.25. Assume vacuum outside the medium.​

Answer 1

Let's use the snel's law.
Snell's Law states that the ratio of the sines of the angles of incidence and refraction is equal to the ratio of the refractive indices of the two media:

sin(i)/sin(r) = n2/n1

Where i is the angle of incidence, r is the angle of refraction, n1 is the refractive index of the first medium (in this case, vacuum), and n2 is the refractive index of the second medium (in this case, the dielectric).

Since vacuum has a refractive index of 1 and the dielectric constant of the medium is 1.25, the refractive index of the medium is also 1.25.

Plugging in the values we have:

sin(20)/sin(r) = 1.25/1

sin(r) = sin(20)/1.25

sin(r) = 0.321

r = sin^-1(0.321)

r = 18.6 degrees

Therefore, the angle of refraction within the medium is approximately 18.6 degrees.