1. When we see an object, we continue to see it for some time even after the object is removed. This phenomenon is called persistence of vision. It lasts for about one sixteenth of a second.
2. Accommodation of eye is the ability of eye to change its focal length so that we can see both distant and nearby object clearly.
It is achieved by the contraction and and relaxation of the ciliary muscle. When the ciliary muscle contracts, the lens gets stretched and the focal length increases and we can see the distant objects clearly. When the ciliary muscle relaxes, it contracts the lens and the focal length of the lens decreases and we can see nearby objects clearly.
3. Scattering of light is the phenomenon in which the light is scattered by the particles in the medium.
The intensity "I" is inversely proportional to the 4th power of wavelength or