Through which of the following mediums is the velocity of a soundwave the greatest? steel water lead air

Steel is the medium in which the velocity of sound wave is greatest.

Explanation:

The speed at which light in solids are faster when compared to gases and  liquids. This is because the molecules in the solid are tightly packed when compared to the molecules arrangement in gases and liquids. The sound travels 17 times faster in solids than in other states of matter.

Lead is also solid. But the arrangement molecules is more tight and compact in steel than in lead. Thus, in steel the speed at which the sound travels  is 5960m/s whereas the speed of sound in lead is 1960m/s .

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;