Related Questions

In a city 40% of the people have black hair, 25% have black eyes and 10% have both black hair and black eyes. What percentage of the people in the city has neither black hair nor black eyes?
A 35
B 40
C 45
D 50
In a certain city 40% of the people have black hair, 25% have black eyes and 10% have both black hair and black eyes. What percentage of the people in the city have neither black hair nor black eyes?
A 35
B 40
C 45
D 50
If the wavelengths corresponding to ultraviolet, visible and infrared radiations are given as lUV, lVIS and lIR respectively, then which of the following gives the correct relationship among these wavelengths?
A lUV < lIR < lVIS
B lUV > lVIS > lIR
C lUV > lIR > lVIS
D lUV < lVIS < lIR
Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an __________ body.
A Grey
B Black
C Opaque
D White
Heat transfer by radiation from a hot body will be most rapid, if its surface is __________ because of its higher emissivity.
A White & rough
B Black & rough
C White & polished
D Black & polished
When heat is transferred from 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
Which of the following determine the kind (wavelength) and amount of radiation that an object emits?
A Temperature
B Thermal conductivity
C Density
D Latent heat
The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)
A α.T
B α.$$\frac{1}{{\text{T}}}$$
C α.T4
D Independent of T
A black body does not __________ radiation.
A Absorb or emit
B Refract
C Reflect
D Both B & C
A perfect black body is a perfect __________ of radiation.
A Absorber
B Emitter
C Both A & B
D Neither A nor B

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