A. nature of body
B. temperature of body
C. type of surface of body
D. all of the above
E. none of the above
0
The ratio of the energy absorbed by the body to total energy falling on it is called_________________?
0
The emissive power of a body depends upon its___________________?
A. absorptive power
B. emissive power
C. absorptivity
D. emissivity
E. none of the above
0
40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is____________________?
A. temperature
B. wave length
C. physical nature
D. all of the above
E. none of the above
0
The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit_______________?
A. 0.45
B. 0.55
C. 0.40
D. 0.75
E. 0.60
0
Depending on the radiating properties, a body will be black when_________________?
A. temperature
B. thickness
C. area
D. time
E. area and time
0
According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to____________________?
A. p = 0, x = 0 and a = 1
B. p= l,T = 0anda = 0
C. p = 0, x = 1 and a = 0
D. x = 0, a + p = 0
E. a = 0,x + p= 1.
where a = absorptivity, p == reflectivity, X = transmissivity
0
The thermal diffusivities for solids are generally__________________?
A. absolute temperature
B. T2
C. T5
D. t
E. l/T
0
The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as_________________?
A. less than those for gases
B. jess than those for liquids
C. more than those for liquids and gases
D. more or less same as for liquids and gases
E. zerci
0
Depending on the radiating properties, a body will be white when_________________?
A. Krichoff’s law
B. Stefan’s law
C. Wien’ law
D. Planck’s law
E. Black body law
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