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# Condensation And Boiling Online Exam Quiz

Important questions about Condensation And Boiling. Condensation And Boiling MCQ questions with answers. Condensation And Boiling exam questions and answers for students and interviews.

### Boiling refers to a change from the

Options

A : a. Solid to a liquid phase

B : b. Vapor to a liquid phase

C : c. Liquid to a solid phase

D : d. Liquid to a vapor phase

### The boiling process has wide-spread applications in (i) Production of steam in nuclear and steam power plants for generation and for industrial processes and space heating (ii) Absorption of heat in refrigeration and air-conditioning systems (iii) Concentration, dehydration and drying of foods and materials Identify the correct statements

Options

A : a. 1 and 2

B : b. 2 and 3

C : c. 1, 2 and 3

D : d. 1 and 3

### Maximum heat transfer rate in a modern boiler is about

Options

A : a. 2 * 10? W/m²

B : b. 3 * 10? W/m²

C : c. 4 * 10? W/m²

D : d. 5 * 10? W/m²

### Which type of boiling occurs in steam boilers employing natural convection?

Options

A : a. Forced convection

B : b. Pool

C : c. Local

D : d. Saturated

### In which type of boiling the fluid motion is induced by external means?

Options

A : a. Pool

B : b. Local

C : c. Forced convection

D : d. Subcooled

Options

A : a. Subcooled

B : b. Forces

C : c. Saturated

D : d. Pool

Options

A : a. Forced

B : b. Saturated

C : c. Pool

D : d. Saturated

### The phenomenon of stable film boiling is referred to as

Options

A : a. Nucleate effect

B : b. Boiling regimes

C : c. Leiden frost effect

D : d. Von karma effect

Options

A : a. 25 K

B : b. 55 K

C : c. 75 K

D : d. 105 K

Options

A : a. 1

B : b. 2

C : c. 3

D : d. 4

### When evaporation takes place at the liquid-vapor interface, the heat transfer is solely due to free convection and the film coefficient follows the relation

Options

A : a. Nu = f 1 (G r) f 2 (P r)

B : b. Nu = 2 f 1 (G r) f 2 (P r)

C : c. Nu = 3 f 1 (G r) f 2 (P r)

D : d. Nu = 4 f 1 (G r) f 2 (P r)

### Fritz criterion is given by

Options

A : a. h = 1.973 (Q/A)^0.45

B : b. h = 1.973 (Q/A)^0.55

C : c. h = 1.973 (Q/A)^0.65

D : d. h = 1.973 (Q/A)^0.75

### A 0.10 cm diameter and 15 cm long wire has been laid horizontally and submerged in water at atmospheric pressure. The wire has a steady state voltage drop of 14.5 V and a current of 42.5 A. Determine the heat flux of the wire. The following equation applies for water boiling on a horizontal submerged surface H = 1.54 (Q/A)^0.75 = 5.58 (d t)³ W/m² K where Q/A is the heat flux rate in W/m² and d t is the temperature difference between surface and saturation.

Options

A : a. 1.308 * 10? W/m²

B : b. 1.308 * 10? W/m²

C : c. 1.308 * 10? W/m²

D : d. 1.308 * 10? W/m²

Options

A : a. 4

B : b. 1 and 2

C : c. 1

D : d. 3 and 4

### The heat flux in nucleate boiling varies in accordance with

Options

A : a. h f g

B : b. (h f g)?

C : c. 1/(h f g)²

D : d. (h f g)³

### In nucleate pool boiling, the heat flux depends on

Options

A : a. Liquid properties, material and condition of the surface

B : b. Material of the surface only

C : c. Material and roughness of the surface

D : d. Liquid properties and material of the surface

### Identify the wrong statement with respect to boiling heat transfer?

Options

A : a. The steam boilers employing natural convection have steam raised through pool boiling

B : b. Boiling occurs when a heated surface is exposed to a liquid and maintained at a temperature lower than the saturation temperature of the liquid

C : c. Leiden-frost effect refers to the phenomenon of stable film boiling

D : d. The nucleation boiling is characterized by the formation of bubbles at the nucleation sites and the resulting liquid agitation

### Estimate the peak heat flux for water boiling at normal atmospheric pressure. The relevant thermo-physical properties are p f (liquid) = 958.45 kg/m³ p g (vapor) = 0.61 kg/m³ h f g = 2.25 * 10? J/kg ? = 0.0585 N/m

Options

A : a. 1.53 * 10? W/m²

B : b. 1.53 * 10? W/m²

C : c. 1.53 * 10? W/m²

D : d. 1.53 * 10? W/m²

Options

A : a. 6.15 V

B : b. 7.15 V

C : c. 8.15 V

D : d. 9.15 V

### Condensation refers to a change from the

Options

A : a. Solid to a liquid phase

B : b. Vapor to a liquid phase

C : c. Liquid to a solid phase

D : d. Liquid to a vapor phase