It is difficult to clean daily.
Black surface is a good conductor of heat.
Black surface is a poor conductor of heat.
Black surface is a good absorber of heat.
Ozone at the higher level of the atmosphere is a product of _ acting on oxygen molecules.
Ozone protects biosphere from
Parabolic mirors are used in
Parallax of one arc secondтАЦ is a unit of which of the following?
Pasteurisation of milk means-
Permissible noise level at Residential area during night time is :
Persistance of vision is the principle behind
Persistence of vision is the Principle behind:
Persons suffering from myopia are advised to use
Photon is the fundamental unit/ quantum of