Viscosity of gases ______________ with increase in temperature?

Related Mcqs:

1. For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally ?

   A. Decreases
   B. Increases
   C. Remains unchanged
   D. Increases exponentially

2. Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?

   A. 35.5
   B. 43.75
   C. 81.25
   D. 48.25

3. If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?

   A. Parabolic
   B. Hyperbolic
   C. Linear
   D. Logarithmic

4. The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2. The flux, when the element temperature is increased to 1000°C for the same furnace temperature is_____________________?

   A. 11.2 kW/m2
   B. 12.0 kW/m2
   C. 14.6 kW/m2
   D. 16.5 kW/m2

5. If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows ____________ law?

   A. Hyperbolic
   B. Parabolic
   C. Linear
   D. Logarithmic

6. A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?

   A. t = 283 s
   B. t = 356 s
   C. t = 400 s
   D. t = 800 s

7. A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of material A is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is ______________ °C?

   A. 6
   B. 12
   C. 18
   D. 24

8. At constant temperature, the thermal conductivities of gases _____________ with rise in pressure?

   A. Decrease
   B. Increase
   C. Remain unchanged
   D. May increase or decrease; depends on the pressure

9. With increase in temperature, the thermal conductivity of most liquids_________________?

   A. Increases
   B. Decreases
   C. Remain same
   D. First increases upto a certain temperature and then becomes constant

10. With the increase of temperature, the Col-burn jH factor_____________________?

    A. Increases
    B. Decreases
    C. Remains unchanged
    D. May increase or decrease; depending on temperature