E-PolyLearning

11. In case of homogeneous plane wall, there is a linear temperature distribution given by
a. t = t₁ + (t₂-t₁) δ/x
b. t = t₂ – (t₂-t₁) x/ δ
c. t = t₁ + (t₂-t₁) x
d. t = t₁ + (t₂-t₁) x/ δ
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Answer: (d).t = t₁ + (t₂-t₁) x/ δ

12. The rate of convective heat transfer between a solid boundary and adjacent fluid is given by
a. Q = h A (ts – tf)
b. Q = h A
c. Q = (ts – tf)
d. Q = h (ts – tf)
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Answer: (a).Q = h A (ts – tf)

13. A homogeneous wall of area A and thickness δ has left and right hand surface temperatures of 0 degree Celsius and 40 degree Celsius. Determine the temperature at the center of the wall
a. 10 degree Celsius
b. 20 degree Celsius
c. 30 degree Celsius
d. 40 degree Celsius
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Answer: (b).20 degree Celsius

14. A rod of 3 cm diameter and 20 cm length is maintained at 100 degree Celsius at one end and 10 degree Celsius at the other end. These temperature conditions are attained when there is heat flow rate of 6 W. If cylindrical surface of the rod is completely insulated, determine the thermal conductivity of the rod material
a. 21.87 W/m degree
b. 20.87 W/m degree
c. 19.87 W/m degree
d. 18.87 W/m degree
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Answer: (d).18.87 W/m degree

15. A composite wall generally consists of
a. One homogenous layer
b. Multiple heterogeneous layers
c. One heterogeneous layer
d. Multiple homogenous layers
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Answer: (b).Multiple heterogeneous layers

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