A. high thickness of insulation
B. high vapour pressure
C. less thermal conductivity insulator
D. a vapour seal
E. all of the above
Related Mcqs:
- The insulation ability of an insulator with the presence of moisture would_________________?
A. increase
B. decrease
C. remain unaffected
D. may increase/decrease depending on temperature and thickness of insulation
E. none of the above - When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by __________________?
A. conduction
B. convection
C. radiation
D. conduction and convection
E. convection and radiation - When heat is Transferred by molecular collision, it is referred to as heat transfer by __________________?
A. conduction
B. convection
C. radiation
D. scattering
E. convection and radiation - Thermal conductivity of non-metallic amorphous solids with decrease in temperature __________________?
A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on temperature
E. unpredictable - Sensible heat is the heat required to __________________?
A. change vapour into liquid
B. change liquid into vapour
C. increase the temperature of a liquid of vapour
D. convert water into steam and superheat it
E. convert saturated steam into dry steam - Stefan Boltzmann law is applicable for heat transfer by __________________?
A. conduction
B. convection
C. radiation
D. conduction and radiation combined
E. convection and radiation combined - Thermal diffusivity of a substance is __________________?
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 - If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of___________________?
A. 3
B. 6
C. 9
D. 27
E. 81 - Absorptivity of a body will be equal to its emissivity___________________?
A. at all temperatures
B. at one particular temperature
C. when system is under thermal equi-librium
D. at critical temperature
E. for a polished body - Heat flows from one body to other when they have_________________?
A. different heat contents
B. different specific heat
C. different atomic structure
D. different temperatures
E. none of the above
