Heat Transfer

conduction ✘ convection ✘ radiation ✘ conduction and convection ✔ convection and radiation. ✔

blast furnace ✘ heating of building ✘ cooling of parts in furnace ✘ heat received by a person from fireplace ✔ all of the above. ✔

liquids ✘ energy ✘ temperature ✘ entropy ✔ enthalpy. ✔

face area ✘ time ✘ thickness ✘ temperature difference ✔ thermal conductivity. ✔

their atoms collide frequently ✘ their atoms-are relatively far apart ✘ they contain free electrons ✘ they have high density ✔ all of the above. ✔

I.C. engine ✘ air preheaters ✘ heating of building in winter ✘ all of the above ✔ 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 ✔ convert saturated steam into dry steam. ✔

free electrons ✘ atoms colliding frequency ✘ low density ✘ porous body ✔ all of the above. ✔

increases ✘ decreases ✘ remains constant ✘ may increase or decrease depending on temperature ✔ none of the above. ✔

0.1

✘

0.23

✘

0.42

✘

0.51

✔

0.64.

✔