Category: Heat Transfer

A. I.C. engine
B. air preheaters
C. heating of building in winter
D. all of the above
E. none of the above

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

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

A. aluminium
B. steel
C. brass
D. copper
E. lead

A. 3
B. 6
C. 9
D. 27
E. 81

A. different heat contents
B. different specific heat
C. different atomic structure
D. different temperatures
E. none of the above

A. varies with temperature
B. varies with the wave length of incident ray
C. varies with both
D. does not vary with temperature and wave length of the incident ray
E. there is no such criterion

A. change vapour into liquid
B. change liquid into vapour
C. increase the temperature of a liquid or vapour
D. convert water into steam and superheat it
E. convert saturated steam into dry steam

A. a dimensionless parameter
B. function of temperature
C. used as mathematical model
D. a physical property of the material
E. useful in case of heat transfer by radiation

A. p = 0, x = 0 and a = 1
B. p= l,T = 0anda = 0
C. p = 0, x = 1 and a = 0
D. x = 0, a + p = 0
E. a = 0,x + p= 1.
where a = absorptivity, p == reflectivity, X = transmissivity