Question

3. Give reasons:a. An object seen through a prism appears coloured.
b. We are not able to see clearly for some time when we go from bright sunlight to
a dark room.
c. It is very useful to us that all surfaces do not give regular reflection.

Answer 1

Answer:

a).prism has the ability to scatter the light in different colour.

so if we see any object through prism ,it appears in colour according to its wavelength.

b)pupil has the ability to adjust its size according to light.

so when we enter in sunlight ,our pupil gets small,so small amount of light enters in our eyes.

but when we enter in darkroom from sunlight,

our pupil takes sometime adjust itself in a manner so that more and more light can enter through it.thats why we are not able to see clearly for sometime when we go from bright sunlight to a dark room.

c).because of laws of reflection:

smooth surface has plane area ,so at every point light reflect in a regular manner.

but rough surface has irregular area, so at every point light reflect in iregular manner.