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4

Dowtherm is a

A. High temperature heating medium (a petroleum product)

B. Product of coal tar distillation

C. Very heat sensitive material

D. None of these

Correct Answer :

A. High temperature heating medium (a petroleum product)


Related Questions

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4

The diffusion co-efficient of Ni in Cu at 1000 K is 1.93 × 10-16 m2S-1 and it is 1.94 × 10-14 m2S- 1 at 1200 K. The activation energy (in k. J.mole-1) for the diffusion of Ni in Cu is

A. 130

B. 180

C. 230

D. 250

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4

One face of a furnace wall is at 1030°C and the other face is exposed to room temperature (30°C). If the thermal conductivity of furnace wall is 3 W. m- 1. k-1 and the wall thickness is 0.3 m, the maximum heat loss (in W/m) is

A. 100

B. 900

C. 9000

D. 10000

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4

Silicon in steel

A. Makes it usable in almost all magnetic circuits where alternating current is used

B. Increases its electrical resistivity and decreases the hysteresis loss

C. Is present upto 5% & 4% respectively when used in transformers & motor armatures

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

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4

Which of the following has the least value of ultimate tensile strength (UTS)?

A. Medium carbon steel

B. High carbon steel

C. Cast iron

D. Wrought iron

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4

Catalyst used in the 'catalytic converter' employed in automobile exhaust line for complete combustion/oxidation of carbon monoxide, nitrogen oxides and hydrocarbons is

A. Alumina

B. Platinum

C. Vanadium pentoxide

D. Iron oxide

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4

Heat transfer by __________ is almost absent in case of fluidised bed drying operation.

A. Radiation

B. Conduction

C. Convection

D. Both (B) & (C)

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4

In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be

A. Conduction

B. Radiation

C. Natural convection

D. Forced convection

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4

Pick out the wrong statement

A. Processing of thermosetting plastics is ideally done by injection moulding

B. Processing of thermoplastics is ideally done by compression moulding

C. Mass production of seamless pipes are done by electrical resistance welding (ERW)

D. Stretch forming is a process of cold drawing

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4

__________ is the process used for setting up compressive stresses in the surface of a metal to improve its fatigue strength.

A. Lancing

B. Shot peening

C. Slugging

D. Spinning

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4

An atom bomb works on the principle of

A. Nuclear fission

B. Nuclear fusion

C. Both the nuclear fission & fusion

D. Ionisation

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4

Unit of viscosity in CGS system is

A.

B.

C.

D.

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4

Which of the following is not a principal alloying element for the structural steel?

A. Molybdenum

B. Nickel

C. Manganese

D. Chromium

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4

Diamagnetic materials

A. Are magnetised by eddy currents only

B. Are non-magnetic and cannot be magnetised

C. Are magnetised in direction opposite to the magnetic field

D. Can be magnetised in one direction only

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4

The capacity of a spring to store energy is called the spring form co-efficient. Stiffness of a spring is measured by the

A. Ability to absorb shock

B. Capacity to store energy

C. Ratio of the wire & coil diameters

D. Load to produce unit deflection

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4

With increase in compression ratio, the volumetric efficiency of air compressor

A. Increases

B. Decreases

C. Remain same

D. May increase or decrease (depends on the suction pressure)

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4

Pick out the correct statement.

A. Hot worked materials are subjected to annealing to remove internal stresses

B. Annealing of steel hardens it slightly

C. Normalising of a material induces stresses

D. Tempering of a material improves ductility & toughness but reduces hardness & brittleness

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4

Pressure required to increase the density of water by about 1% is __________ atmosphere.

A. 10

B. 50

C. 200

D. 1000

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4

Stresses encountered in the metal forming processes are less than the __________ of the material.

A. Fracture strength

B. Yield strength

C. Elastic limit

D. Limit of proportionality

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4

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

A. 0.5

B. 1

C. 1/3

D. 2.5

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4

Pressure exerted by a liquid depends upon its

A. Surface tension

B. Density

C. Viscosity

D. Buoyancy

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4

Closeness of packing is maximum in case of __________ crystal lattice.

A. Face centred

B. Simple cubic

C. Body centred

D. None of these

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4

A solar cell converts the sunlight directly into __________ energy.

A. Thermal

B. Electrical

C. Mechanical

D. Chemical

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4

Transformer cores are normally made from

A. Soft ferrites

B. High purity iron

C. Grain oriented Fe-Si alloy

D. Al-Ni-Co alloy

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4

The ability of tool steel to resist softening at high temperatures is termed as __________ hardness.

A. Red

B. Extended

C. Super

D. Extreme

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4

Air/fuel ratio on molar (volume) basis for combustion of methane with theoretical quantity of air with be

A. 9.5 : 1

B. 12.5 : 1

C. 15.5 : 1

D. 18.5 : 1

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4

Fine grained steels have

A. High brittleness

B. Higher tendency to distort

C. High ductility

D. None of these

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4

The unit of gc is

A. lbm/lbf. ft/sec2

B. lbf/lbm. ft/sec2

C. ft/sec2

D. lbm/lbf. sec2/ft

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4

The two elements required to form substitutional solid solution should not have

A. Same crystalline structure

B. Same valency

C. Widely differing electronegativity

D. Same atomic sizes

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4

Which of the following is not the commercial name of poly-methyl-methacrylate (PMMA)?

A. Styrofoam

B. Lucite

C. Perspex

D. Plexiglass

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4

Pick out the wrong statement.

A. The X-rays cannot be deflected by electric field unlike cathode rays

B. The intensity of X-rays can be measured by ionisation current produced due to the ionisation of gas by X-rays

C. The quality of X-rays can be controlled by varying the anode-cathode voltage

D. Crystal structure of a material can be studied by an electron microscope