Presence of moisture in the thermal insulating material increases thermal insulation while the presence of air spaces decreases thermal insulation.

Related MCQs

• Which of the following is not a quality of a good thermal insulating material?
• Reflective sheet materials used as thermal insulating material have                         reflectivity and                      emissivity.
• Thermal insulation keeps the room cool in winters and hot in summers.
• Thermal insulation of roofs can be obtained by covering the top exposed surface of the roof with                  
• A water-heater is covered with insulation boards over a total surface area of 3 m2. The inside board surface is at 75°C and the outside being at 20°C and the conductivity of material being 0.08 W/m K. Find the thickness of board to limit the heat transfer loss to 200 W ?
• A water-heater is covered up with insulation boards over a total surface area of 3 m2. The inside board surface is at 75°C and the outside surface is at 20°C and the board material has a conductivity of 0.08 W/m K. How thick a board should it be to limit the heat transfer loss to 200 W ?
• Batch collectors reduce heat loss by thermally insulating the storage tank.
• The average thermal conductivities of water and air conform to the ratio
• Which of the following is the correct relationship between thermal resistance and thermal conductivity?
• Which of the following is the correct relation between thermal transmittance and thermal time constant?