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Current Affairs January 2024

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4

Water hammer is caused in steam carrying pipelines, because of

A. Partial condensation of steam

B. Vibration of the pipeline

C. High degree of superheat of steam

D. Its exposure to torrential rain

Correct Answer :

A. Partial condensation of steam


Related Questions

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4

Volumetric composition of flue gas analysed with the Orsat apparatus is : CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that

A. Pure oxygen has been used for combustion

B. Nitrogen percentage in the fuel is very high

C. Excess air has been used for combustion

D. Hydrogen is not present in the fuel

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4

Which of the following is an example of stress corrosion?

A. Season cracking of brass

B. Caustic embrittlement of steel

C. Both (A) & (B)

D. Neither (A) nor (B)

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4

Which of the following does not have a sharp melting point?

A. Thoria

B. Glass

C. Ice

D. Pig iron

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4

Which of the following is an ore dressing operation?

A. Classification

B. Smelting

C. Roasting

D. None of these

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4

Which of the following is the largest quantum of pressure?

A. 1 kg/cm2

B. 1 bar

C. 1 atmosphere

D. 1 kilo Pascal

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4

Liquid nitrogen containers can be made from

A. Ferritic stainless steel

B. HSLA steel

C. Titanium

D. Austenitic stainless steel

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4

Which of the following is used to produce draught in the locomotive boilers?

A. Chimney

B. Induced draught fan

C. Forced draught fan

D. Steam jet arrangement

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4

Presence of nickel & chromium in steel does not raise its

A. Elastic limit

B. Machining properties

C. Ductility

D. Resilience

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4

Evaporative cooling process employs a combination of cooling and humidification in which the

A. Sensible heat is added

B. Sensible heat is removed and the latent heat is added

C. Latent heat is removed

D. Sensible heat is added and latent heat is removed

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4

An example of unsteady non uniform flow is the flow of liquid under pressure through a

A. Tapering pipe at constant flow rate

B. Tapering pipe at either decreasing or increasing flow rate

C. Long pipeline of constant diameter

D. None of these

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4

The underground well of a biogas plant is called the

A. Septic tank

B. Oxidation well

C. Digestor

D. Lagoon

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4

Wohler test is a destructive test to find out the __________ strength of a prepared metal specimen.

A. Creep

B. Fatigue

C. Endurance

D. Tensile

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4

The fugacity of liquid water at 298 K is approximately 3171 Pa. Considering the ideal heat of vaporisation as 43723 J/gm.mole, its fugacity at 300 K would be

A. 3171Pa

B. 3567Pa

C. 1.01 × 105Pa

D. 5000Pa

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4

Wrought iron is not

A. Ductile & resistant to corrosion/rusting

B. Weldable easily

C. Having uniform strength in all directions

D. Having maximum tensile strength along the lines of slag distribution

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4

Load cells used for the measurement of weight has

A. Compact & rugged construction with an accuracy of 0.1 to 1%

B. No moving parts and incurs negligible deflection under load

C. Provision of thermal compensation and is hermetically sealed

D. All 'a', 'b' & 'c'

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4

Metalloids

A. Are good conductor of heat & electricity

B. Act as electron donors with metals & as electron acceptor with non-metals

C. Are not necessarily solids at room temperature

D. Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron

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4

Electrical conductivities of semi-conductors are of the order of __________ ohm/cm.

A. 10-3

B. 103

C. 10-15

D. 1015

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4

Pick out the wrong statement.

A. Both annealing and normalising release the internal stresses of the material besides improving the mechanical properties

B. Low carbon steel does not respond to the heat treatment for hardening of the material, hence it is subjected to case hardening or surface hardening processes like cyaniding, carburising, nitriding etc., which produces high carbon outer layers resulting in increase of surface hardness

C. Induction hardening and flame hardening techniques are also used for surface hardening

D. Martempering of a material is a hardening process

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4

Hydrogen in liquid steels is dissolved

A. As tiny gas bubbles

B. In the atomic form

C. In the ionic form

D. In the molecular form

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4

'GASOHOL' widely used in Brazil as a motor fuel is a mixture of alcohol and

A. Petrol

B. LPG

C. Light hydrocarbon gases (e.g. butane or propane)

D. None of these

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4

Silicon percentage in acid resistant cast iron is about

A. 4

B. 8

C. 14

D. 20

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4

With increase in __________ Knocking tendency in a spark ignition petrol engine decreases.

A. Supercharging

B. Wall temperature

C. Compression ratio

D. Engine speed

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4

Addition of __________ to steel does not help in improving its machinability.

A. Sulphur

B. Silicon

C. Lead

D. Phosphorous

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4

Use of water as a manometric liquid suffers from the disadvantage of its

A. Low vapour pressure

B. Corrosive nature

C. High vapour pressure

D. High boiling point

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4

Large scale fire on fuel gas line is normally extinguished by

A. Water

B. Steam

C. Foam

D. Nitrogen

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4

The lightest non-inflammable gas is

A. H2

B. He

C. Ar

D. O2

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4

The product (s) of roasting of a sulphide ore is (are)

A. Oxide only

B. Sulphate only

C. Oxide and sulphate

D. Dependent on temperature and partial pressure of oxygen & sulphur dioxide

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4

Work required for compression of a gas contained in a cylinder is 7000 kJ. During compression, heat interaction of 3000 kJ causes the surroundings to be heated. Internal energy change of the gas during the compression is __________ kJ.

A. +4000

B. -4000

C. 10000

D. -10000

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4

Temperature of hot gases flowing in a pipe is measured by a thermocouple inserted in the thermal well. The thermal well made of __________ will facilitate the most accurate measurement of the temperature.

A. Copper

B. Steel

C. Aluminium

D. Brass

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4

Steam condenser tubes are made of admiralty brass, in which percentage of zinc & copper are __________ respectively.

A. 70 & 30

B. 30 & 70

C. 50 & 50

D. 90 & 10