A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/

CuriousTab

CuriousTab

Home Aptitude

Discussion

Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments

Question
A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14 W/mK and thickness
Options
A. 0.5 m
B. 0.1 m
C. 0.2 m
D. 0.5 m

Correct Answer

0.1 m

Heat Transfer, Refrigeration and Air Conditioning problems

Search Results

2. In a vapour compression system, the condition of refrigerant is dry saturated vapour
Options
A. before entering the compressor
B. after leaving the compressor
C. before entering the condenser
D. after leaving the condenser

3. A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be
Options
A. 1.33
B. 2.33
C. 3.33
D. 4.33

5. In order to collect liquid refrigerant and to prevent it from going to a __________ , a device known as accumulator is used at the suction of compressor.
Options
A. compressor
B. condenser
C. expansion valve
D. evaporator

10. A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is
Options
A. h₁ + h₂ + h₃
B. (h₁h₂h₃)^1/3
C.
D. none of these

Comments

More in Mechanical Engineering: