Answer: Option B. -> Heat always flow in the direction of negative temperature gradient Answer: (b).Heat always flow in the direction of negative temperature gradient
Question 4. Consider the following statements: The Fourier heat conduction equation Q = -k A d t /d x Presumes i) Steady state conditions ii) Constant value of thermal conductivity iii) Uniform temperature at the wall surface iv) One dimensional heat flow Which of these statements are correct?
Answer: Option C. -> Non- linear temperature profile Answer: (c).Non- linear temperature profile
Question 6. The diagram shows heat conduction through a plane wall. The surface temperature is 475 K and it radiates heat to the surroundings at 335 K. If thermal conductivity of the material is 12.5 W/m degree, find the temperature gradient. Let convective coefficient be 80 W/m² degree and radiation factor is 0.9
Question 7. From the concept of kinetic theory, mean travel velocity of the gas molecules is prescribed by the relation (Where, G = Universal gas constant M = Molecular weight of the gas T = Absolute temperature)
Question 9. Low temperature insulation are used when the enclosure is at a temperature lower than the ambient temperature. Which one of the following is not a low temperature insulation?
Answer: Option A. -> Asbestos Answer: (a).Asbestos
Question 10. Consider the following parameters (i) Composition (ii) Density (iii) Porosity (iv) Structure Then, thermal conductivity of glass wool varies from sample to sample because of variation is