Heat Transfer

A. both the fluids at inlet (of heat ex¬changer where hot fluid enters) are in their coldest state
B. both the fluids at inlet are in their hot¬test state
C. both the fluids .at exit are in their hottest state
D. one fluid is in hottest state and other in coldest state at inlet
E. any combination is possible depending on design of heat exchanger

A. one dimensional cases only
B. two dimensional cases only
C. three dimensional cases only
D. regular surfaces having non-uniform temperature gradients
E. irregular surfaces

A. higher
B. lower
C. same
D. depends on the area of heat exchanger
E. depends on temperature conditions

A. radiant heat is proportional to fourth power of absolute temperature
B. emissive power depends on temperature
C. emissive power and absorptivity are constant for all bodies
D. ratio of emissive power to absorptive power is maximum for perfectly black body
E. ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body

A. better insulation should be put over pipe and better one over it
B. inferior insulation should be put over pipe and better one over it
C. both may be put in any order
D. whether to put inferior OIL over pipe or the better one would depend on steam temperature
E. unpredictable

A. cold water inlet and outlet
B. hot medium inlet and outlet
C. hot medium outlet and cold water inlet
D. hot medium outlet and cold water outlet
E. none of the above

A. Grashoff number
B. Nusselt number
C. Weber number
D. Prandtl number
E. Reynold number

A. higher
B. lower
C. same
D. depends upon the shape of body
E. none of the above

A. 1 :1
B. 2: 1
C. 1 : 2
D. 4 : 1
E. 1 : 4

A. thermal resistance
B. thermal coefficient
C. temperature gradient
D. thermal conductivity
E. heat-transfer