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Statement 1: Drop-wise condensation takes place on a smooth surface. Statement 2: All the resistance to heat transfer lies in the film formed during Film-type condensation.

Correct Answer: False, True
Drop-wise condensation does NOT take place on a smooth surface as the drops cannot adhere to the surface.

Consider the following statements (i) If a condensing liquid does not wet a surface, then drop wise condensation will not take place on it (ii) Drop wise condensation gives a higher transfer rate than film wise condensation (iii) Reynolds number of condensing liquid is based on its mass flow rate (iv) Suitable coating or vapor additive is used to promote film wise condensation Identify the correct statement

Statement 1: Film-type condensation has a higher heat transfer co-efficient than drop-wise condensation. Statement 2: Drop-wise condensation is easier to maintain than Film-type condensation

The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation.

Statements : All film stars are playback singers. All film directors are film stars.

Conclusions :
I. All film directors are playback singers.
II. Some film stars are film directors.

Statement 1: When heat transfer takes between a solid surface and a fluid, an insulating film layer is formed. More is the agitation; more is the thickness of the film. Statement 2: Within the film, the temperature varies from the wall to the temperature of the bulk.

A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be

When two fluids of the heat exchanger are separated by a plane wall, the thermal resistance comprises (i) Convection resistance due to the fluid film at the inside surface (ii) Conduction resistance (iii) Convection resistance due to the fluid film at the outside surface Identify the correct option

Consider the following statements.
1. When evaporation takes place, cooling takes place.
2. Evaporation takes place at all temperature, boiling takes place only at the boiling point.
3. Evaporation is a surface phenomenon.
Which of the statements given above is/are true?

A finned surface consists of root or base area of 1m2 and fin surface area of 2m2. The average heat transfer coefficient for finned surface is 20W/m2K effectiveness of fins provided is 0.75. If finned surface with surface with root or base temperature of 50°C is transferring heat to fluid of 30°C, then the rate of heat transfer without using fin is _______

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by