Questions

450 mm Hg denotes the air pressure.

P J Nayak

Heat energy can be transferred by three major methods. They are 

1. Conduction,

2. Convection and

3. Radiation.

Conduction is the movement of heat through a substance by the collision of molecules

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy.

Radiation is the transfer of energy by means of photons in electromagnetic waves governed by the same laws. It occurs through a vacuum or any transparent medium.

Skimming is the removal of any material or particles that are floating on the surface. Hence, Removal of oil and grease from sewage - waste water is called as skimming.

The chemical name of common salt is Sodium Chloride with a chemical formula NaCl.

The Story telling or The narrative form of paintings were the early examples of art photography which were often imitated.

The chemical name of common is sodium chloride. Its chemical formula is NaCl.