A diamond glitters in a brightly lit room, but not in a dark room. Why?

Why does a person not able to see for some time when he comes out of a well lighted room at night or enters a dark room at day time?

Why is it dangerous to burn coal in a closed room?

Which characteristic of the sound help you to identify your friend by this voice while sitting with others in a dark room.

Why diamond is hard while graphite is soft ?

It is difficult to see through a closed glass window from the inside of a well lighted room,when it is dark outside.However,it becomes relatively easy to see outside,when the lights in the room are switched off.Explain.

Measure length, width and height of your class room and find the total area of the room which is to be white washed.