A. is black in colour
B. reflects all heat
C. transmits all heat radiations
D. abslprbs heat radiations of all wave lengths falling on it
E. fully opaque
A. black bodies
B. polished bodies
C. all coloured bodies
D. all of the above
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. more than those for liquids
B. less than those for liquids
C. more than those for solids
D. dependent on the viscosity
E. same as for the liquids
A. directly proportional to thermal con¬ductivity
B. inversely proportional to density of substance
C. inversely proportional to specific heat
D. all of the above
E. none of the above
A. conduction
B. convection
C. radiation
D. conduction and radiation combined
E. convection and radiation combined
A. watt/cm2 °K
B. watt/cm4 °K
C. watt2/cm °K4
D. watt/cm2 °K4
E. watt/cm2 °K2
A. same
B. more
C. less
D. depends on other factors
E. none of the above
A. absolute temperature
B. square of temperature
C. fourth power of absolute temperature
D. fourth power of temperature
E. cube of absolute temperature
A. Grashoff no. and Reynold no
B. Grashoff no and Prandtl no.
C. Prandtl no. and Reynold no
D. Grashoff no., Prandtl no and Reynold no
E. none of the above