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4

The polytropic index (n) is given by

A. log (p1p2)/log (v1v2)

B. log (p2/ p1)/log (v1/ v2)

C. log (v1/ v2)/ log (p1/p2)

D. log [(p1v1)/(p2v2)]

Correct Answer :

B. log (p2/ p1)/log (v1/ v2)


Related Questions

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4

The amount of heat required to raise the temperature of the unit mass of gas through one degree at constant volume, is called

A. Specific heat at constant volume

B. Specific heat at constant pressure

C. Kilo Joule

D. None of these

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4

The smallest quantity of a substance, which can exist by itself in a chemically recognizable form is known as

A. Element

B. Compound

C. Atom

D. Molecule

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4

Mond gas is obtained by

A. Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

B. Carbonisation of bituminous coal

C. Passing steam over incandescent coke

D. Passing air and a large amount of steam over waste coal at about 650°C

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4

For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order

A. Dual cycle, Diesel cycle, Otto cycle

B. Otto cycle, Diesel cycle, Dual cycle

C. Dual cycle, Otto cycle, Diesel cycle

D. Diesel cycle, Otto cycle, Dual cycle

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4

The general gas energy equation is (where Q1 - 2 = Heat supplied, dU = Change in internal energy, and W1 - 2 = Work done in heat units)

A. Q1 - 2 = dU + W1 - 2

B. Q1 - 2 = dU - W1 - 2

C. Q1 - 2 = dU/W1 - 2

D. Q1 - 2 = dU × W1 - 2

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4

Brayton cycle consists' of following four processes

A. Two isothermals and two isentropic

B. Two isentropic and two constant volumes

C. Two isentropic, one constant volume and one constant pressure

D. Two isentropic and two constant pressures

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4

A key is subjected to side pressure as well at shearing forces. These pressures are called

A. Bearing stresses

B. Fatigue stresses

C. Crushing stresses

D. Resultant stresses

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4

The maximum diameter of the hole that can be punched from a plate of maximum shear stress 1/4th of its maximum crushing stress of punch, is equal to (where t = Thickness of the plate)

A. t

B. 2t

C. 4t

D. 8t

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4

Charles' law states that all perfect gases change in volume by __________ of its original volume at 0°C for every 1°C change in temperature, when pressure remains constant.

A. 1/27th

B. 1/93th

C. 1/173th

D. 1/273th

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4

The stress induced in a body, when suddenly loaded, is ________ the stress induced when the same load is applied gradually.

A. Equal to

B. One-half

C. Twice

D. Four times

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4

The compression ratio for Diesel engines is

A. 3 to 6

B. 5 to 8

C. 15 to 20

D. 20 to 30

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4

Carbonisation of coal consists of

A. Drying and crushing the coal to a fine powder

B. Moulding the finely ground coal under pressure with or without a binding material

C. Heating the wood with a limited supply of air to temperature not less than 280°C

D. None of the above

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4

A process of heating crude oil to a high temperature under a very high pressure to increase the yield of lighter distillates, is known as

A. Cracking

B. Carbonisation

C. Fractional distillation

D. Full distillation

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4

All perfect gases change in volume by 1/273th of its original volume at 0°C for every 1°C change in temperature, when the pressure remains constant. This statement is called

A. Boyle's law

B. Charles' law

C. Gay-Lussac law

D. Joule's law

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4

The behaviour of a perfect gas, undergoing any change in the variables which control physical properties, is governed by

A. Boyle's law

B. Charles' law

C. Gay-Lussac law

D. All of these

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4

The temperature at which the volume of a gas becomes zero is called

A. Absolute scale of temperature

B. Absolute zero temperature

C. Absolute temperature

D. None of these

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4

A material obeys hooks law up to

A. Plastic limit

B. Elastic limit

C. Yield point

D. Limit of proportionality

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4

The efficiency and work ratio of a simple gas turbine cycle are

A. Low

B. Very low

C. High

D. Very high

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4

Resilience of a material is considered when it is subjected to

A. Frequent heat treatment

B. Fatigue

C. Creep

D. Shock loading

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4

The energy absorbed in a body, when it is strained within the elastic limits, is known as

A. Strain energy

B. Resilience

C. Proof resilience

D. Modulus of resilience

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4

Proof resilience per material is known as

A. Resilience

B. Proof resilience

C. Modulus of resilience

D. Toughness

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4

When a rectangular beam is loaded transversely, the maximum compressive stress is developed on the

A. Top layer

B. Bottom layer

C. Neutral axis

D. Every cross-section

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4

Strain is equal to (where l = Original length, and δl = Change in length)

A. l/δl

B. δl/l

C. l.δl

D. l + δl

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4

The principal constituents of a fuel are

A. Carbon and hydrogen

B. Oxygen and hydrogen

C. Sulphur and oxygen

D. Sulphur and hydrogen

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4

The property of a material which allows it to be drawn into a smaller section is called

A. Plasticity

B. Ductility

C. Elasticity

D. Malleability

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4

The total elongation produced in a bar of uniform section hanging vertically downwards due to its own weight is equal to that produced by a weight

A. Of same magnitude as that of bar and applied at the lower end

B. Half the weight of bar applied at lower end

C. Half of the square of weight of bar applied at lower end

D. One fourth of weight of bar applied at lower end

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4

A pressure vessel is said to be a thick shell, when

A. It is made of thick sheets

B. The internal pressure is very high

C. The ratio of wall thickness of the vessel to its diameter is less than 1/10.

D. The ratio of wall thickness of the vessel to its diameter is greater than 1/10.

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4

Which of the following statement is incorrect?

A. The liquid fuels consist of hydrocarbons.

B. The liquid fuels have higher calorific value than solid fuels.

C. The solid fuels have higher calorific value than liquid fuels.

D. A good fuel should have low ignition point.

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4

Diesel cycle consists of following four processes

A. Two isothermal and two isentropic

B. Two isentropic and two constant volumes

C. Two isentropic, one constant volume and one constant pressure

D. Two isentropic and two constant pressures

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4

The gas in cooling chamber of a closed cycle gas turbine is cooled at

A. Constant volume

B. Constant temperature

C. Constant pressure

D. None of these