k/h₀
2k/h₀
h₀/k
h₀/2k
The time taken to attain the final temperature to be measured
The time taken to attain 50% of the value of initial temperature difference
The time taken to attain 63.2% of the value of initial temperature difference
Determined by the time taken to reach 100°C from 0°C
Stanton number
Biot number
Peclet number
Grashoff number
Absolute temperature
T²
T⁵
T
Liquids
Energy
Temperature
Entropy
A dimensionless parameter
Function of temperature
Used as mathematical model
A physical property of the material
Less than those for gases
Less than those for liquids
More than those for liquids and gases
More or less same as for liquids and gases
K cal/kg m² °C
K cal m/hr m² °C
K cal/hr m² °C
K calm/hr °C
Conduction
Convection
Radiation
None of these
Direct mixing of hot and cold fluids
A complete separation between hot and cold fluids
Flow of hot and cold fluids alternately over a surface
Generation of heat again and again
Energy transferred by convection to that by conduction
Kinematic viscosity to thermal diffusivity
Inertia force to viscous force
None of the above
h₁ + h₂ + h₃
(h₁.h₂.h₃)1/3
1/h₁ + 1/h₂ + 1/h₃
None of these
Parallel flow type
Counter flow type
Cross flow type
Regenerator type
Absolute temperature
Square of temperature
Fourth power of absolute temperature
Fourth power of temperature
Watt/cm² °K
Watt/cm4 °K
Watt²/cm °K⁴
Watt/cm² °K⁴
Nature of body
Temperature of body
Type of surface of body
All of the above
High thickness of insulation
High vapour pressure
Less thermal conductivity insulator
A vapour seal
At all temperatures
At one particular temperature
When system is under thermal equilibrium
At critical temperature
S.H/(S.H + L.H)
(S.H + L.H) /S.H
(L.H - S.H)/S.H
S.H/(L.H - S.H)
0.1
0.3
0.7
1.7
2 TR
4 TR
8 TR
10 TR
Grashoff number and Reynold number
Grashoff number and Prandtl number
Prandtl number and Reynold number
Grashoff number, Prandtl number and Reynold number
Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state
Both the fluids at inlet are in their hottest state
Both the fluids at exit are in their hottest state
One fluid is in hottest state and other in coldest state at inlet
Change vapour into liquid
Change liquid into vapour
Increase the temperature of a liquid or vapour
Convert water into steam and superheat it
Improve heat transfer
Provide support for tubes
Prevent stagnation of shell side fluid
All of these
Wien's law
Stefan's law
Kirchhoff's law
Planck's law
More than those for liquids
Less than those for liquids
More than those for solids
Dependent on the viscosity
Universal gas constant
Kinematic viscosity
Thermal conductivity
Planck's constant
Absorptive power
Emissive power
Emissivity
None of these
Kirchhoff's law
Stefan's law
Wines law
Planck's law