False - Correct statement: Thermal expansion is always not a nuisance

False - Correct statement: Steam is formed when heat is absorbed front water

True

(i) The measurement of warmness or coldness of a substance is known as its Temperature.
(ii) SI unit of temperature is kelvin

(i) The Water heater
(ii) Iron box
(iii) Electric kettle etc.

The molecules in the solid move faster and vibrate when heating. Spread apart and occupy more space. So solid expands when heated.

The expansion of substance on heating is called, the thermal expansion of that substance 
(i) Gaps are left in between rails while laying railway track :
So that there is enough margin for the tracks to expand and contract due to the temperature changes. If that gap is not left then the tracks might have enormous stress in them while expanding due to heat, which can damage them.
(ii) Gaps are left in between two joints of a concrete bridge:
Thermal expansion takes place due to the increase in the kinetic energy of the constituent molecules as they are heated. Thermal expansion is the reason we leave some gaps between section of h concrete bridge.

The heat is escaping from the room because the room temperature is higherthan atmosphere. Heat energy flows from higher temperature to lower temperature.