With increase in temperature, the thermal conductivity of a gas ___________________?

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. The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K0 + at, where, K is the thermal conductivity and T is the temperature (in °K). The units of ‘a’ in SI system will be________________?

   A. W/m.k
   B. W/m
   C. W/m.k2
   D. None, ‘a’ is just a number

3. With increase in temperature, the thermal conductivity of fresh lubricating oil ___________________?

   A. Increases
   B. Decreases
   C. Remains unchanged
   D. May increase or decrease; depends on its composition

4. 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

5. 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

6. 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

7. 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

8. 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

9. With increase in temperature, the thermal conductivity of non-metallic amorphous solids_________________?

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

10. With increase in temperature, the thermal conductivity of steel___________________?

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