A. Nitrogen
B. Steel
C. Carbon black
D. Tar
Related Mcqs:
- 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 - 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 - Which of the following has maximum thermal conductivity ?
A. Iron
B. Coal
C. Nitrogen
D. Tar - Which of the following has the highest thermal conductivity ?
A. Brick
B. Air
C. Water
D. Silver - 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 - Conductance is given by (where, x = thickness, A = heat flow area, K = thermal conductivity.)?
A. x/KA
B. KA/x
C. K/Ax
D. A/Kx - 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 - Three materials A, B and C of equal thickness and of thermal conductivity of 20, 40 & 60 kcal/hr. m. °C respectively are joined together. The temperature outside of A and C are 30°C and 100°C respectively. The interface between B and C will be at a temperature of ____________ °C?
A. 40
B. 95
C. 70
D. 50 - Low thermal conductivity of heat insulating materials is due to its_______________?
A. Dense structure
B. High proportion of air space
C. High specific heat
D. None of these - Thermal conductivity of a conducting solid material depends upon its_______________?
A. Temperature
B. Porosity
C. Both A. & B.
D. Neither A. nor B.
