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. 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. 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. black bodies
B. polished bodies
C. all coloured bodies
D. all of the above
E. none of the above
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. 3
B. 6
C. 9
D. 27
E. 81
A. direct mixing of hot and cold fluids
B. a complete separation between hot and cold fluids
C. flow of hot and cold fluids alternately over a surface
D. generation of heat again and again
E. indirect transfer
A. convection
B. free convection
C. forced convection
D. radiation
E. radiation and convection
A. p = 0, x = 0 and a = 1
B. p=l,x = 0,anda = 0
C. p = 0, T= l,anda = 0
D. X = 0, a + p = 1
E. a = 0,x + p= 1