A. watt/cm2 °K
B. watt/cm4 °K
C. watt2/cm °K4
D. watt/cm2 °K4
E. watt/cm2 °K2
Related Mcqs:
- According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to___________________?
A. absolute temperature
B. square of temperature
C. fourth power of absolute temperature
D. fourth power of temperature
E. cube of absolute temperature - 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 - According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to____________________?
A. absolute temperature
B. T2
C. T5
D. t
E. l/T - Heat conducted througfi unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called__________________?
A. thermal resistance
B. thermal coefficient
C. temperature gradient
D. thermal conductivity
E. heat-transfer - The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as ________________?
A. emissivity
B. transmissivity
C. reflectivity
D. intensity of radiation
E. absorptivity - The time constant of a thermocouple is_______________?
A. the time taken to attain the final temperature to be measured
B. the time taken to attain 50% of the value of initial temperature difference
C. the time taken to attain 63.2% of the value of initial temperature difference
D. determined by the time taken to reach 100°C from 0°C
E. none of the above - Thermal conductivity of water in general with rise in temperature ____________________?
A. increases
B. decreases
C. remains constant
D. may increase or decrease depending on temperature
E. none of the above - Temperature of steam at around 540°C can be measured by ____________________?
A. thermometer
B. radiatiouv pyrometer
C. thermistor
D. thermocouple
E. thermopile - Thermal diffusivity of a substance is ____________________?
A. proportional of thermal conductivity
B. inversely proportional to k
C. proportional to (k)
D. inversely proportional to k2
E. none of the above - Thermal diffusivity is ____________________?
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
