Light Reflection and Refraction Test - 15

Upon passage through a triangular glass prism, the white light is separated into its component colors - red, orange, yellow, green, blue, indigo and violet. The separation of visible light into its different colors is known as dispersion. The light that will emerge out of the combination of the two prisms, will be white in colour.

By convention, the three primary colors in are red, green, and blue. When blue colour is mixed with green colour, cyan colour is obtained.

As a ray of light travels from a denser medium to a rarer medium, it bends away from the normal.

For a fixed incident ray, the angle of the reflection will be twice the angle through which the mirror has rotated. After reflection, a ray of light is reflected by an angle about the normal. The reflected ray follows the law of reflection according to which the angle of reflection is always equal to the angle of incidence. When the mirror is rotated by an angle Q, the normal (which is perpendicular to the mirror) also rotates by the same angle Q. So the ray of light is also rotated at an angle Q about the normal. Hence, the total rotation of the reflected ray is given by:

Q (angle between the incident ray and normal at the point of incidence) + Q (angle between and the new reflected ray and the new normal at the point of incidence) = 2Q

Plane mirrors are generally used to demonstrate reflection of light in laboratories since it is easier to draw the normal to a plane mirror at the point of incidence and trace the reflected ray.

The mirror can be either a plane mirror or a convex mirror. A convex mirror always forms an erect, and a virtual and diminished image, for any position of the object. A plane mirror also forms an erect image.

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