Theoretical volume of oxygen required for complete combustion of 1 Nm3 of acetylene, in oxy-acetylene welding is __________ Nm3 .

Theoretical volume of oxygen required for complete combustion of 1 Nm<sup>3</sup> of acetylene, in oxy-acetylene welding is __________ Nm<sup>3</sup> .

Which of the following statement(s) is/are true regarding butt welding? 1. Flash butt welding is a combination of resistance, arc and pressure welding 2. Upset butt welding is used for welding rods 3. Percussion Welding is a self timing spot welding method 4. Aluminium alloys are flash welded

A

1, 2, and 3

B

Only 2 and 3

C

2, 3, and 4

D

Only 1 and 4

In a gas welding of mild steel using an oxyacetylene flame, the total amount of acetylene consumed is 10 litres. The oxygen consumption from the cylinder is

A

5 litres

B

10 litres

C

15 litres

D

20 litres

Which of the following statements is correct regarding the oxidation number of Oxygen? I. The oxidation number of Oxygen in most compounds is -2. II. When Oxygen is bonded to Fluorine in compounds like Oxygen difluoride and Dioxygen diflouride, the Oxygen is assigned an oxidation number of +2 and +2 respectively. III. In peroxide, an Oxygen atom is assigned an oxidation number of -1 and in Superoxide, each oxygen atom is assigned an oxidation number of -1/2.

A

I only

B

II only

C

I and III only

D

I, II, and III

The pressure of acetylene in welding torch for oxy-acetylene welding is maintained at _________

A

0.66-1.0 bar

B

0.1-3.5 bar

C

0.5-3.5 bar

D

1.0-4.5 bar

Which of the following are essential for a good combustion chamber of turbojet engine? 1. It should allow complete combustion of fuel. 2. It should maintain sufficiently high temperature in the zone of combustion in addition to proper atomization of fuel thus leading to continuous combustion. 3. It should not have high rate of combustion. 4. The pressure drop should be as small as possible

A

1, 2 and 4 only

B

1, 2 and 3 only

C

1, 3 and 4 only

D

2, 3 and 4 only

Find the volume of air required for complete combustion of 1 m3 of acetylene and the weight of air necessary for the combustion of 1 kg of fuel?

A

10.6 m3 and 12.526 kg

B

12.1 m3 and 15.5 kg

C

11.9 m3 and 13.378 kg

D

12.0 m3 and 14.965 kg

Consider the following statements: In metal arc welding 1. Utilizes a consumable electrode 2. A welding torch used is connected to acetylene gas supply 3. The electrode and work-piece are connected to the welding power supply. Which of these statements are correct?

A

1, 2 and 3

B

1 and 2 only

C

1 and 3 only

D

2 and 3 only

Oxy acetylene welding and oxy-hydrogen welding are the examples of ____ welding.

A

gas

B

air

C

resistance

D

friction

Electrical resistance welding is preferred over oxyacetylene and arc welding for joining P/M parts.

A

True

B

False

In a well aerated and agitated microbial culture, the 'supply' of oxygen is equal to 'demand' (uptake) of the growing culture. The K_La for such a system will be (K_La = volumetric mass transfer coefficient, C* = dissolved oxygen concentration in liquid in equilibrium with gaseous oxygen, C = instantaneous value of dissolved oxygen concentration, 'r' = specific oxygen uptake rate per unit weight of cells, X = dry weight of the cells per unit volume)

A

$$\frac{{\left( {rX} \right)}}{{\left( {C* - C} \right)}}$$

B

$$\frac{{\left( r \right)}}{{X\left( {C* - C} \right)}}$$

C

$$\frac{{\left( {C* - C} \right)}}{{\left( {rX} \right)}}$$

D

$$\frac{{\left( X \right)}}{{r\left( {C* - C} \right)}}$$

Theoretical volume of oxygen required for complete combustion of 1 Nm³ of acetylene, in oxy-acetylene welding is __________ Nm³ .

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