Human Eye and Colourful World Test - 11

According to Snell’s law, ratio of the sine of the angle of incidence to the sine of the angle of refraction is always constant for a given pair of media. Therefore, if the angle of incidence increases, the angle of refraction also increases proportionally to the increase of incidence.

The lateral displacement of an incident ray passing out of a rectangular glass slab is directly proportional to the thickness of glass slab, angle of incidence, and refractive index however it is inversely proportional to the wavelength of incident light.

Advance Sunrise and delayed  sunset: This  is  due  to atmospheric  refraction. Because of this sun is visible about 2 minutes earlier than actual sunrise and about 2 minutes after  the actual  sun  set.

In myopia, a person can  see nearby object clearly, but cannot  see distant object distinctly. Image formed in front of the retina.

It is due to: 

1. Elongation of  the eye ball

2. Excessive curvature of eye  lens  (thick eye lens---> decrease in focal  length---> increase in power of lens)

Twinkling of stars is due to atmospheric refraction. Distant star acts like a point source of light. When the starlight enters the earth’s atmosphere it undergoes refraction continuously, due to changing refractive index i.e. from Rarer to denser medium. It bends towards the normal successively, hence the amount of light enters our eyes fluctuates sometime bright and sometime faint.

Red colour  scattered  the  least when  strikes  by the  small particle of  fog and smoke because it has the maximum wavelength (visible spectrum). Hence at  large distance also, we can  see  the  red colour clearly.

Applications of optical fiber include:

1. Communication: Telephone transmissoin method usese fiber-optic cables. Optical fibres transmit energy in the form of light pulses.

2. Medical uses: Optical fibres are well suited for medical use. They can be made in extremely thin, flexible stands for insertion into the blood vessels, lungs, and other hollow parts of the body. Optical fibers are used in a number of instruments that enable doctors to view internal body parts without having to perform surgery.

3. Simple uses: The simplest application of optical fibers is the trnsmission of light to locations otherwise hard to reach.

The retinal cones of bees are sensitive to ultraviolet light. Hence bees respond to ultraviolet light.