Take some pieces of papers of leaf size and make them waterproof. Put half in the hot water and put half in the cold water do all the pieces remains waterproof

No.

Explanation:

No, all the pieces of paper did not remains waterproof because expansion of paper occur due to high temperature of hot water. We know that materials expand when they experience high temperature and contract when they observe cold temperature. So the pieces of paper remains waterproof which were put in cold water while those were not waterproof which were put in hot water.

vapour or gas assuming atmospheriv pressure

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.