Practice Test: Question Set - 19
1. In the equation Q = UAΔt; Δt is
- (A) Geometric mean temperature difference
- (B) Arithmetic mean temperature difference
- (C) Logarithmic mean temperature difference
- (D) The difference of average bulk temperatures of
hot and cold fluids
2. Convective heat transfer, in which heat is transferred by movement of warmed matter is described by
- (A) Fourier's law
- (B) Newton's law of cooling
- (C) Fick's law
- (D) None of these
3. For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in
- (A) Increased economy
- (B) Decreased economy
- (C) Lower capacity
- (D) No effect on economy
4. Which of the following has the minimum absorptivity?
- (A) Aluminium foil
- (B) Coal dust
- (C) Refractory bricks
- (D) Iron plates
5. Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3/min) of density 800 kg/m3 and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately
- (A) 32
- (B) 37
- (C) 45
- (D) 50
6. In a forward feed multiple effect, the pressure build up will be
- (A) Least at the inlet of the first effect
- (B) Least at the outlet of the last effect
- (C) Highest at the inlet of the last effect
- (D) Highest at the outlet of the last effect
7. Graetz number is given by
- (A) mCp/kL
- (B) kL/mCp
- (C) mCp/kµ
- (D) kµ/mCp
8. Thermal diffusivity is given by
- (A) k/ρCp
- (B) ρCp/k
- (C) µCp/a
- (D) µ/hCp
9. The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the
- (A) Heating volume
- (B) Heat transfer area
- (C) Nusselt number
- (D) None of these
10. Reynold's analogy states that
- (A) Nst α f
- (B) Nst α NRe
- (C) NNu α f
- (D) NRe α f
11. In case of a vertical tube evaporator, with increase in the liquor level, the
- (A) Capacity of the evaporator is decreased
- (B) Capacity of the evaporator is increased
- (C) True temperature drop increases
- (D) Both (b) and (c)
12. Which of the following has the minimum thermal conductivity?
- (A) Nitrogen
- (B) Steel
- (C) Carbon black
- (D) Tar
13. Low thermal conductivity of heat insulating materials is due to its
- (A) Dense structure
- (B) High proportion of air space
- (C) High specific heat
- (D) None of these
14. For an ideal black body
- (A) Absorptivity = 1
- (B) Reflectivity = 1
- (C) Emissivity = 0
- (D) Transmissivity = 1
15. In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always
- (A) < 1
- (B) > 1
- (C) 1
- (D) ∞
Next Tests:
Blogger Comment
Facebook Comment