an unpolarised light is incident on the boundary between two transparent media. State the contition when the reflected wave is totally plane polarised.
To determine the condition when the reflected wave is totally plane polarized at the boundary between two transparent media, you need to consider the phenomenon of reflection and polarization.
First, let's understand what an unpolarized light is. Unpolarized light consists of electromagnetic waves vibrating in all possible planes perpendicular to the direction of propagation. It can be thought of as a mixture of waves vibrating in different planes.
When unpolarized light is incident on the boundary between two transparent media, some of the light is reflected and some is transmitted (refracted) into the second medium. The reflected wave can be partially or completely polarized, depending on the angle of incidence and the refractive indices of the media.
The condition for the reflected wave to be totally plane polarized is known as Brewster's Law. According to Brewster's Law, when light is incident on a boundary with a particular angle known as the Brewster's angle (θB), the reflected wave becomes completely plane polarized, with the electric field of the reflected wave vibrating only in one plane parallel to the boundary.
Brewster's Law can be mathematically stated as follows:
tan(θB) = n2 / n1
Where:
θB is the Brewster's angle.
n1 is the refractive index of the first medium.
n2 is the refractive index of the second medium.
To find the Brewster's angle, you need to know the refractive indices of the two media involved. Once you have the values of n1 and n2, you can use the equation above to calculate the Brewster's angle (θB).
By setting the angle of incidence equal to the Brewster's angle, you can ensure that the reflected wave becomes totally plane polarized.
In summary, the condition for the reflected wave to be totally plane polarized at the boundary between two transparent media is to have the angle of incidence equal to the Brewster's angle, which can be determined using Brewster's Law and the refractive indices of the media involved.