In: Physics
How do you describe the ray pattern of light? What is the value of the speed of light in a vacuum and in any medium? How is the law of reflection expressed for a wave? How is the refractive index of a medium defined? How is Snell's law for light expressed and what is the mathematical expression?
A light ray is a line (straight or curved) that is perpendicular to the light's wavefronts, its tangent is collinear with the wave vector.
The speed of the light in a vacuum is c=3x10^{8}m/s.The speed of the light in a medium is v=c/n=[(3x 10^{8})/n ]m/s. [n is the refractive index of the medium.]
The Law of reflection is defined as -"angle of the incident ray with normal to the interface is equals with the angle of the reflection ."
The refractive index of a medium is defined as the ratio of the speed of light in a vacuum to that of the speed of light in the medium.
Snell’s law, in optics, a relationship between the path taken by a ray of light in crossing the boundary or surface of separation between two contacting substances and the refractive index of each.
n1 and n2 represent the indices of refraction for the two media, and α1 and α2 are the angles of incidence and refraction that the ray R makes with the normal then Snell’s law asserts that
n1/n2 = sin α2/sin α1.