Practice Test: Question Set - 13
1. At constant temperature, the thermal conductivities of gases __________ with rise in pressure.
- (A) Decrease
- (B) Increase
- (C) Remain unchanged
- (D) May increase or decrease; depends on the
pressure
2. Stefan-Boltzmann law applies to __________ body.
- (A) Black
- (B) White
- (C) Grey
- (D) Any color
3. When warm and cold liquids are mixed, the heat transfer is mainly by
- (A) Conduction
- (B) Convection
- (C) Radiation
- (D) Both (a) & (c)
4. A BTU/hr.ft.2 °F is equal to
- (A) 1 kcal/hr. m2°C
- (B) 4.88 kcal/hr. m.2°C
- (C) 1 kcal/hr. m2.°K
- (D) None of these
5. Open pan evaporators are preferred to be used, when the solution to be concentrated is
- (A) Scaling
- (B) Highly viscous
- (C) Corrosive
- (D) Salty
6. A __________ evaporator employs an annular downtake.
- (A) Basket type
- (B) Horizontal
- (C) Long tube vertical
- (D) None of these
7. The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy.
- (A) Von-Karman
- (B) Reynolds
- (C) Colburn
- (D) Prandtl
8. The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is
- (A) Lower tube side pressure drop
- (B) Lower shell side pressure drop
- (C) Higher tube side heat transfer co-efficient
- (D) Higher shell side heat transfer co-efficient
9. With increase in temperature, the thermal conductivity of fresh lubricating oil
- (A) Increases
- (B) Decreases
- (C) Remains unchanged
- (D) May increase or decrease; depends on its composition
10. Vent pipes are provided in a condenser to
- (A) Remove non-condensable gases
- (B) Purge the condenser
- (C) Facilitate easy cleaning of tubes
- (D) None of these
11. To reduce the tube side pressure drop for the same flow rate, the heat exchanger recommended is
- (A) 1-2 heat exchanger
- (B) 1-1 heat exchanger
- (C) 3-2 heat exchanger
- (D) 2-4 heat exchanger
12. LMTD for counter-flow and parallel flow heat exchanger will be the same, when the
- (A) Cold fluid is heated to a certain temperature by condensing steam
(isothermal fluid)
- (B) Outlet temperature of both the hot and cold fluid are same
- (C) Outlet temperature of hot fluid is less than the outlet temperature
of the cold fluid
- (D) None of these
13. In case of __________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface.
- (A) Nucleate
- (B) Local
- (C) Pool
- (D) Saturated
14. Steam trap is used to
- (A) Condense the steam flowing in the pipeline
- (B) Remove water resulting from partial condensation of steam
- (C) Stop the supply of steam
- (D) None of these
15. For __________ Prandtl number values, the heat conduction will be negligible in the buffer zone.
- (A) Extremely low
- (B) Low
- (C) High
- (D) No
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