Thermal conductivity is defined as the heat flow per unit time

Related MCQs

• The specific heat of the substance is defined as the amount of heat required to raise a unit mass of the substance through a unit rise in temperature.
• Which of the following is the correct relationship between thermal resistance and thermal conductivity?
• Presence of moisture in the thermal insulating material increases thermal insulation while the presence of air spaces decreases thermal insulation.
• A large heat exchanger transfers a total of 100 MW. Assume the wall separating steam and seawater is 4 mm of steel, conductivity 15 W/m K and that a maximum of 5°C difference between the two fluids is allowed. Find the required minimum area for the heat transfer.
• The amount of heat flow through a unit area of material of unit thickness in one hour, when the temperature difference is maintained at 1°C is known as                         of the material.
• Which of the following is the correct relation between thermal transmittance and thermal time constant?
• A composite wall is made of two layers of thickness δ1 and δ2 having thermal conductivities k and 2k and equal surface area normal to the direction of heat flow. The outer surface of composite wall are at 100 degree Celsius and 200 degree Celsius. The minimum surface temperature at the junction is 150 degree Celsius. What will be the ratio of wall thickness?
• Mark the matter with least value of thermal conductivity
• Which one of the following forms of water have the highest value of thermal conductivity?
• The reciprocal of thermal conductivity is known as