In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface?

Related Mcqs:

1. 1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be__________________?

   A. 15 min
   B. 22 min
   C. 44 min
   D. 51 min

2. A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?

   A. t = 283 s
   B. t = 356 s
   C. t = 400 s
   D. t = 800 s

3. In case of _____________ boiling, the bubbles formed on a submerged hot surface get absorbed in the mass of the liquid?

   A. Nucleate
   B. Pool
   C. Low pressure
   D. None of these

4. 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

5. 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

6. A hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case ?

   A. The cooling rate will be the same for the two spheres and hence the two spheres will have
   equal temperatures at any instant
   B. Both the spheres will emit equal amount of radiation per unit time in the beginning
   C. Both will absorb equal amount of radiation from the surrounding in the beginning
   D. Both B. & C.

7. If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?

   A. Parabolic
   B. Hyperbolic
   C. Linear
   D. Logarithmic

8. If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows ____________ law?

   A. Hyperbolic
   B. Parabolic
   C. Linear
   D. Logarithmic

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

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

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