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Current Affairs January 2024

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4

All the atoms of the world comprise of electrons, proton & neutron except that of __________ atom in which neutron is absent.

A. Deuterium

B. Hydrogen

C. Neon

D. Helium

Correct Answer :

B. Hydrogen


Related Questions

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With increase in annealing temperature, the following defect density decreases.

A. Vacancy

B. Dislocation

C. Grain boundary

D. All of these

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__________ joint is usually used for joining cast iron pipes mostly used for temporary pipelines, where it may be necessary to dismantle & reassemble the pipeline very frequently.

A. Collar

B. Flanged

C. Bell and Spigot

D. Expansion

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4

What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m2. °K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively.

A. 2

B. 8

C. 10

D. 40

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4

In Imperial Smelting Process for extraction of zinc, zinc vapour thus produced is quenched in the external condenser by the use of the following:

A. Jet of water at high pressure

B. Blast of air

C. Mixture of water and air

D. Rain of molten lead

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In case of compression of one kg of air, the work done will be the least, when the value of polytropic index 'n' is

A. 1

B. 1.4

C. 1.5

D. Y = Cp/Cv

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Which of the following is an ore dressing operation?

A. Classification

B. Smelting

C. Roasting

D. None of these

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Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore?

A. High fusibility & fluidity

B. High thermal conductivity

C. Low density

D. High chemical activity

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4

The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the 'Curie temperature'. Its value for cobalt is __________ °C.

A. 768

B. 1127

C. 1359

D. 1480

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4

Thermistors are used in __________ devices.

A. Voltage measuring

B. Temperature measuring

C. Temperature compensating

D. Both (B) & (C)

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Which of the following is the correct nature of shear stress distribution along the cross section in a horizontal circular pipe under steady state fluid flow condition?

A.

B.

C.

D.

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Out of the following substances, one ton of __________ will store the maximum heat for a rise of 30°C in temperature.

A. Steel

B. Lignite

C. Water

D. Lime stone

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A highly elastic material is deformed least on loading and retains its original form on removal of the load. Which of the following is the most elastic material?

A. Steel

B. Glass

C. Rubber

D. Brass

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4

The ratio of thermal & electrical conductivity is same for all the metals at the same temperature; and at around room temperature, this ratio is proportional to(where, T = absolute temperature, °K)

A. T

B. 1/T

C. T2

D. 1/T2

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4

Tip of the match stick contains a mixture of

A. K + S

B. K + S + K2Cr2O7

C. S + K2Cr2O7 + White P

D. None of these

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4

In the X-ray radiography technique, the tube voltage for thicker plates as compared to thin plates, should be

A. Higher, as it gives higher wavelength

B. Lower, as it gives higher wavelength

C. Higher, as it gives shorter wavelength

D. Lower, as it gives shorter wavelength

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Which of the following terminology is used for the temperature at which new grains are formed in a metal?

A. Eutectic temperature

B. Lower critical temperature

C. Recrystallisation temperature

D. Upper critical temperature

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4

Hydro-cyclone is a

A. Crusher

B. wet classifier

C. Dry classifier

D. Magnetic separator

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Normalising does not __________ of a metal.

A. Improve machinability & tensile strength

B. Remove internal stresses

C. Refine the structure

D. Remove strains caused by cold working

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A solar cell converts the sunlight directly into __________ energy.

A. Thermal

B. Electrical

C. Mechanical

D. Chemical

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Methyl orange indicator turns

A. Orange yellow in alkaline medium

B. Orange yellow in acidic medium

C. Colourless in acidic medium

D. Colourless in basic medium

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The yield point phenomenon observed in annealed low carbon steel is due to the presence of the following element.

A. Silicon

B. Carbon

C. Phosphorous

D. Chromium

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Laser welding is widely employed in the __________ industries.

A. Electronic

B. Structural

C. Process

D. Heavy

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The 'transition temperature' for ductile to brittle behaviour of steel increases with increase in the __________ content in steel.

A. Carbon

B. Manganese

C. Both 'a' nor 'b'

D. Neither 'a' nor 'b'

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Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an __________ body.

A. Grey

B. Black

C. Opaque

D. White

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Wavelength of radiation emitted by a body depends on the __________ of its surface.

A. Temperature

B. Area

C. Nature

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

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Pick out the wrong statement about coating/electroplating of metals.

A. Phosphate coating is used as an excellent base for paints & enamels

B. Phosphate coating is less corrosion resistant than chromate coating

C. The base metal to be electroplated is normally made the cathode of the electrolytic cell and coating metal is made the anode

D. Calorising is the process of coating steel with chromium

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Out of the following, the most malleable material is

A. Copper

B. Aluminium

C. Wrought iron

D. Lead

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An oxidation process is accompanied with decrease in the

A. Number of electrons

B. Oxidation number

C. Number of ions

D. All (A), (B) & (C)

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If Reynolds number is greater than 1, then the

A. Viscous force is larger than the inertia force

B. Inertia force is larger than the viscous force

C. Inertia force is larger than the surface tension force

D. Inertia force is larger than the gravitational force

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Carbon supply in pack carburising process is in the form of

A. Charcoal

B. Calcium carbide

C. Hydrocarbon oil

D. Graphite