Can you give simple definition of entropy?

Adiver named jacques observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the surface (where the pressure is 1.00 atm). the temperature at the bottom is 4.00 ∘c, and the temperature at the surface is 23.0 ∘c.what is the ratio of the volume of the bubble as it reaches the surface (vs) to its volume at the bottom (vb)? if jaques were to hold his breath the air in his lungs would be kept at a constant temperature. would it be safe for jacques to hold his breath while ascending from the bottom of the lake to the surface?

Energy can be transformed from one form to another. the diagram shows one such process. which energy transformation is represented in the diagram? nuclear to thermal and radiant nuclear to electrical and chemical chemical to nuclear and radiant chemical to electrical and nuclear

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this