In geometrical optics, a ray of light is defined as

Options

A. path of propagation of light
B. path of propagation of shadows
C. direction of formation of image
D. path of propagation of energy for `lamda to 0`

Answer

D

Explanation

In geometrical optics, a ray is defined as the path of energy propagation in the limit of wavelength tending to zero. The wavelength of visible light was measured and found to be extremely small, e.g. the wavelength of yellow light is about `0.5mum`. Because of the smallness of the wavelength of visible light (in comparison to the dimensions of typical mirrors and lenses), light can be assumed to approximately travel in straight lines.