A. Decreases
B. Increases
C. Remain constant
D. First decreases upto certain temperature and then increases
Related Mcqs:
- 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 - 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 - 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 - 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 - 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 - 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 - 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 - With increase in temperature, the thermal conductivity of a gas ___________________?
A. Increases
B. Decreases
C. Remain same
D. May increase or decrease depending on the type of gas - 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 - With increase in temperature, the thermal conductivity of steel___________________?
A. Increases
B. Decreases
C. Remains unchanged
D. Increases exponentially
