In sub-cooled boiling ?

Related Mcqs:

1. 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

2. Boiling point elevation for a strong and concentrated solution is found by Duhring’s rule, which states that at the same pressure, the boiling point of a solution is a linear function of the _______________ of pure water?

   A. Boiling point
   B. Dynamic viscosity
   C. Kinematic viscosity
   D. Density

3. Boiling of milk in an open vessel is an example of ______________ boiling?

   A. Film
   B. Sub-cooled
   C. Saturated nucleate
   D. None of these

4. In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is ________________?

   A. More
   B. Less
   C. Same
   D. More or less; depends on the nature of solution

5. Mode of heat transfer involved in the cooling of air cooled internal combustion engine is_________________?

   A. Conduction
   B. Natural convection
   C. Forced convection
   D. None of these

6. Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because___________________?

   A. Convection becomes important
   B. Conduction becomes important
   C. Radiation becomes important
   D. Sub-cooled boiling occurs

7. Boiling point of a solution according to Duhring’s rule is a linear function of the _____________ of water?

   A. Boiling point (at the same pressure)
   B. Viscosity
   C. Density
   D. Thermal conductivity

8. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is____________________?

   A. 3.06 × 105
   B. 6.12 × 105
   C. 7.24 × 105
   D. 9.08 × 105

9. When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as ___________________ boiling?

   A. Pool
   B. Nucleate
   C. Transition
   D. Film

10. As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient ?

    A. Continues to increase
    B. Continues to decrease
    C. Goes through a minimum
    D. Goes through a maximum