Geometrical Optics

Q.

Ray optics is valid, when characteristic dimensions are

1. Of the same order as the wavelength of light

2. Much smaller than the wavelength of light

3. Of the order of one millimeter

4. Much larger than the wavelength of light

Q. The "Ray" model of light fails to explain the optical phenomena when

1. the light is travelling in any media other than vacuum
2. the wavelength of the light is very small as compared to the dimensions of openings it interacts with
3. the wavelength of the light is comparable to the dimensions of the openings it encounters
4. none of the above.

Q.

Ray and Beam.