I.C. engine

air preheaters

heating of building in winter

none of the above.

change vapour into liquid

change liquid into vapour

increase the temperature of a liquid or vapour

convert water into steam and superheat it

free electrons

atoms colliding frequency

low density

porous body

increases

decreases

remains constant

may increase or decrease depending on temperature

0.1

0.23

0.42

0.51