The pressure at which latent heat of vaporisation of water is zero, is_________________?

Related Mcqs:

1. The critical pressure at which latent heat of vaporisation is zero is________________?

   A. 225.65 kgf/cm2
   B. 273 kgf/cm2
   C. 100 kgf/cm2
   D. 1 kgf/cm2
   E. – 1 kgf/cm2

2. The latent heat of steam at pressures greater than atmospheric in comparison to latent heat at atmospheric pressure is__________________?

   A. less
   B. more
   C. equal
   D. may be less or more depending on temperature
   E. unpredictable

3. At critical point, i.e. p=225.65 kg/cm2, the latent enthalpy of vaporisation is______________?

   A. maximum
   B. minimum
   C. zero
   D. depends on temperature also
   E. none of the above

4. Latent heat of dry steam at atmospneric pressure is equal to____________________?

   A. 539 kcal/kg
   B. 539 BTU/lb
   C. 427 kcal/kg
   D. 100 kcal/kg
   E. 471 kcal/kg

5. The latent heat of steam with increase of pressure__________________?

   A. remains same
   B. increases
   C. decreases
   D. behaves unpredictably
   E. none of the above

6. In water wall furnace, the heat is transferred to the water-walls by _________________?

   A. convection
   B. radiation
   C. conduction
   D. radiation and conducton
   E. radiation and convection

7. To avoid vaporisation in the pipe line, the pipe line over the ridge is laid such that it is not more than____________________?

   A. 2.4 m above the hydraulic gradient
   B. 6.4 m above the hydraulic gradient
   C. 10.0 m above the hydraulic gradient
   D. 5.0 above the hydraulic gradient
   E. none of the above

8. Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler _________________?

   A. increases
   B. decreases
   C. remains unaffected
   D. first increases and then decreases
   E. first decreases and then increases

9. At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be_________________?

   A. minimum
   B. maximum
   C. zero
   D. negative value
   E. could be any value

10. The ratio of heat utilised to produce steam and the heat liberated in furnace is known as___________________?

    A. boiler effectiveness
    B. boiler evaporative capacity
    C. factor of evaporation
    D. equivalent evaporation
    E. boiler efficiency