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91.

The value of Stefan Boltzmann's constant in kcal-m2-hr-k4 is

A.	56.7 x 10-9	B.	1.335 x 10-12
C.	4.87 x 10-8	D.	0.174 x 10-8
E.	0.567 x 10-4

92.

A relationship between the temperature of a black body and the wavelength at which the maximum value of monochromatic emission power occurs, is established under

A.	D' lambert's rule	B.	Wein's displacement law
C.	Stefan-Bolzmann's law	D.	Kirchhoff's law
E.	Planck's law

93.

At all wavelengths and temperatures the monochromatic emissivity of a white body is equal to

A.	Zero	B.	0.1 to 0.5
C.	0.5	D.	0.5 to 1
E.	Unity

94.

All temperatures above the freezing point of gold are usually determined by

A.	Thermo couple	B.	Gas thermometer
C.	Optical pyrometer	D.	Resistance bridge
E.	Any of the above

95.

Identity the correct statement

A.	Bodies black in colour are known as black bodies	B.	Only some substances emit radiation
C.	Quality and quantity of radiation depends on the properties of the material only	D.	A substance will emit radiation at a particular wavelength only
E.	All substances emit radiation the quality and quantity depends on the absolute temperature and the properties of the material composing the radiating body

96.

The surface which diffusely reflects and emits the same amount of energy which it receives by radiation is known as

A.	A perfect black surface	B.	A perfect grey surface
C.	A perfect white surface	D.	A perfect radiating surface
E.	None of the above

97.

Plank's law of radiation is applicable to

A.	Radiation of any kind	B.	Temperature radiation
C.	Monochromatic radiation	D.	Thermal radiation
E.	None of the above

98.

The radiation from flames consists of

A.	Continuous radiation from burning soot particles of microscopic and submicroscopic dimensions	B.	Radiation from suspended larger particles of coal, coke or ash contributing to flame luminosity
C.	Infrared radiation from water vapour and carboundioxide	D.	Non-equilibrium radiation associated with the combustion process
E.	All of the above

99.

In the electrical network analysis method the total radiation which leaves a surface per unit time per unit area is termed as

A.	Radiosity	B.	Irradiation
C.	Flux	D.	Spatial resistance
E.	Potential

100.

The net radiant interchange per square metre for two large parallel planes at temperatures of 1000?K and 100?K respectively, would be roughly

A.	25 kcal/hr	B.	75 kcal/hr
C.	120 kcal/hr	D.	240 kcal/hr
E.	480 kcal/hr