What is the absorptivity of a black body?
What is the absorptivity of a black body?
A. 1
B. 0
C. 0.78
D. 0.95
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C. Both A. and B.
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B. Form friction
C. Both A. and B.
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Heat transfer co-efficient equation for forced convection, Nu = 0.023 Re 0.8. Pr n, is not valid, if the value of __________________?A. n = 0.4 is used for heating
B. n = 0.3 is used for cooling
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D. Reynolds number for the flow involved is < 2100Steady state one dimensional heat flow by conduction as given by Fourier’s low does not assume that_______________?
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D. Constant temperature gradient exists_____________ equation relates the thermal conductivity of a solid to its temperature ?
_____________ equation relates the thermal conductivity of a solid to its temperature ?A. Antoine
B. Kopp’s
C. Lee’s
D. KistyakowskyThermal conductivity of a gas at low density, ___________ with increase in temperature ?
Thermal conductivity of a gas at low density, ___________ with increase in temperature ?A. Decreases
B. Increases
C. Remains unchanged
D. May increase or decrease; depends on the gas