MCQs

Total Questions : 70 | Page 2 of 7 pages
Question 11. The rate of convective heat transfer between a solid boundary and adjacent fluid is given by
1.    Q = h A (ts – tf)
2.    Q = h A
3.    Q = (ts – tf)
4.    Q = h (ts – tf)
Answer: Option A. -> Q = h A (ts – tf)
Answer: (a).Q = h A (ts – tf)
Question 12. 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
1.    10 degree Celsius
2.    20 degree Celsius
3.    30 degree Celsius
4.    40 degree Celsius
Answer: Option B. -> 20 degree Celsius
Question 13. In case of homogeneous plane wall, there is a linear temperature distribution given by
1.    t = t₁ + (t₂-t₁) δ/x
2.    t = t₂ – (t₂-t₁) x/ δ
3.    t = t₁ + (t₂-t₁) x
4.    t = t₁ + (t₂-t₁) x/ δ
Answer: Option D. -> t = t₁ + (t₂-t₁) x/ δ
Answer: (d).t = t₁ + (t₂-t₁) x/ δ
Question 14. A composite wall generally consists of
1.    One homogenous layer
2.    Multiple heterogeneous layers
3.    One heterogeneous layer
4.    Multiple homogenous layers
Answer: Option B. -> Multiple heterogeneous layers
Question 15. 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
1.    21.87 W/m degree
2.    20.87 W/m degree
3.    19.87 W/m degree
4.    18.87 W/m degree
Answer: Option D. -> 18.87 W/m degree
Question 16. “Radiation cannot be affected through vacuum or space devoid of any matter”. True or false
1.    True
2.    False
3.    May be
4.    Can't say
Question 17. The rate of heat conduction through a cylindrical tube is usually expressed as
1.    Per unit length
2.    Per unit area
3.    Only length
4.    Only area
Answer: Option A. -> Per unit length
Question 18. Typical examples of heat conduction through cylindrical tubes are not found in
1.    Power plants
2.    Oil refineries
3.    Most process industries
4.    Aircrafts
Question 19. A composite slab has two layers having thermal conductivities in the ratio of 1:2. If thickness is same for each layer then the equivalent thermal conductivity of the slab would be
1.    1/3
2.    2/3
3.    2
4.    4/3