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Which of the following is the correct statement of the second law of thermodynamics?

A. It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work.

B. It is impossible to transfer heat from a body at a lower temperature to a higher temperature, without the aid of an external source.

C. There is a definite amount of mechanical energy, which can be obtained from a given quantity of heat energy.

D. All of the above

Correct Answer :

D. All of the above


Related Questions

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If the radius of wire stretched by a load is doubled, then its Youngs modulus will be

A. Doubled

B. Halved

C. Becomes four times

D. None of the above

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When coal is first dried and then crushed to a fine powder by pulverising machine, the resulting fuel is called

A. Wood charcoal

B. Bituminous coal

C. Briquetted coal

D. None of these

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4

The value of 1 mm of Hg is equal to

A. 1.333 N/m2

B. 13.33 N/m2

C. 133.3 N/m2

D. 1333 N/m2

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Hooke's law holds good up to

A. Yield point

B. Limit of proportionality

C. Breaking point

D. Elastic limit

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The mass of excess air supplied is equal to

A. (23/100) × Mass of excess carbon

B. (23/100) × Mass of excess oxygen

C. (100/23) × Mass of excess carbon

D. (100/23) × Mass of excess oxygen

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4

The bending equation is

A. M/I = σ/y = E/R

B. T/J = τ/R = Cθ/l

C. M/R = T/J = Cθ/l

D. T/l= τ/J = R/Cθ

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The change in the unit volume of a material under tension with increase in its Poisson's ratio will

A. Increase

B. Decrease

C. Remain same

D. Increase initially and then decrease

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If the rivets in adjacent rows are staggered and the outermost row has only one rivets, the arrangement of the rivets is called

A. Chain riveting

B. Zigzag riveting

C. Diamond riveting

D. Crisscross riveting

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Reversed Joule cycle is known as

A. Carnot cycle

B. Bell-Coleman cycle

C. Rankine cycle

D. Stirling cycle

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If the value of n = 0 in the equation pvn = C, then the process is called

A. Constant volume process

B. Adiabatic process

C. Constant pressure process

D. Isothermal process

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Carnot cycle has maximum efficiency for

A. Petrol engine

B. Diesel engine

C. Reversible engine

D. Irreversible engine

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A double strap butt joint with equal straps is

A. Always in single shear

B. Always in double shear

C. Either in single shear or double shear

D. None of these

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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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In case of an under-reinforced beam, the depth of actual neutral axis is __________ that of the critical neutral axis.

A. Same as

B. Less than

C. Greater than

D. None of these

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According to Regnault's law, the specific heat at constant pressure (cp) and specific heat at constant volume (cv) _________ with the change in pressure and temperature of the gas.

A. Change

B. Do not change

C. Both (A) and (B)

D. None of these

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According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.

A. Equal to

B. Directly proportional to

C. Inversely proportional to

D. None of these

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The energy stored in a body when strained within elastic limit is known as

A. Resilience

B. Proof resilience

C. Strain energy

D. Impact energy

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The shear force diagram of a cantilever beam of length l and carrying a uniformly distributed load of w per unit length will be

A. A right angled triangle

B. An isosceles triangle

C. An equilateral triangle

D. A rectangle

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A process, in which the working substance neither receives nor gives out heat to its surroundings during its expansion or compression, is called

A. Isothermal process

B. Hyperbolic process

C. Adiabatic process

D. Polytropic process

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Youngs modulus of a wire is defined as the stress which will increase the length of wire compared to its original length by

A. Half

B. Same amount

C. Double

D. One-fourth

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4

In open cycle gas turbine plants

A. The indirect heat exchanger and cooler is avoided

B. Direct combustion system is used

C. A condenser is used

D. All of the above

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In the below figure, curve D represents_________.

A. Mild steel

B. Cast iron

C. Concrete

D. Bone of these

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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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The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle)

A. (T1/T2) - 1

B. 1 - (T1/T2)

C. 1 - (T2/T1)

D. 1 + (T2/T1)

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According to First law of thermodynamics,

A. Total internal energy of a system during a process remains constant

B. Total energy of a system remains constant

C. Workdone by a system is equal to the heat transferred by the system

D. Internal energy, enthalpy and entropy during a process remain constant

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The heat and mechanical energies are mutually convertible. This statement was established by

A. Boyle

B. Charles

C. Joule

D. None of these

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The bending moment at a point on a beam is the algebraic ________ of all the moments on either side of the point.

A. Sum

B. Difference

C. Multiplication

D. None of the above

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In a prismatic member made of two materials so joined that they deform equally under axial stress, the unit stresses in two materials are

A. Equal

B. Proportional to their respective moduli of elasticity

C. Inversely proportional to their moduli of elasticity

D. Average of the sum of moduli of elasticity

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The intensity of stress which causes unit strain is called

A. Unit mass

B. Modulus of rigidity

C. Bulk modulus

D. Modulus of Elasticity

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Strain energy is the

A. Energy stored in a body when strained within elastic limits

B. Energy stored in a body when strained up to the breaking of a specimen

C. Maximum strain energy which can be stored in a body

D. Proof resilience per unit volume of a material