PHYSICS

The heat added to the solid is absorbed by the particles and it is utilised in overcoming the intermolecular force of attraction between the particles. So heat absorbed in solids is changed to potential energy without any change in kinetic energy of the molecules. As temperature in Kelvin scale is the measure of kinetic energy of particles, there is no change in temperature during melting.

Cloud appears white due to the phenomena of scattering of white light. The water particles in the cloud are big in size as compared to air molecules and wavelength of light. Hence all the colours get scattered in equal intensity and mixture of all colours gives white light. This white light reaches our eyes giving the impression that colour of a cloud is white.

Water has high specific heat capacity . It absorbs large amount of heat from the surrounding without  much rise in its temperature .Hence the temperature falls .

The cause of magnetism is the flow of an electric charge. The rest charge is associated with an electric field only but the moving charges are associated with both electric and magnetic fields.

The escape velocity of the moon is less than the average velocity of the atom or molecule of  gases. Hence all gas molecules escape out of moon's gravitational field .

Earthing is required in a circuit when 1. the appliance draws high current. High power devices draw large current.(Current =power/voltage). 2. the appliance has outer metallic case.

It is longer so that when we put the plug into the socket, earth connection is made first for the safety. It is thicker so that it is not inserted to the holes of live and neutral. It has split ends so that the plug is fitted firmly into the socket to avoid sparking.