Thermodynamics

31. The heat transfer from a higher temperature object to a lower temperature object is an example of:

a) Adiabatic process

b) Isothermal process

c) Heat conduction

d) Heat convection

32. The entropy of a perfect crystal at absolute zero temperature is:

a) Zero

b) Positive

c) Negative

d) Infinite

33. The efficiency of a Carnot engine operating between two temperatures, Th and Tc, is maximum when:

a) Th is maximum

b) Tc is maximum

c) Th – Tc is maximum

d) Th / Tc is maximum

34. The heat transfer through a vacuum is primarily by:

a) Conduction

b) Convection

c) Radiation

d) Both conduction and convection

35. The efficiency of a heat engine is always less than:

a) 0%

b) 25%

c) 50%

d) 100%