Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle
Combustion is at constant volume
Expansion and compression are isentropic
Maximum temperature is higher
Heat rejection is lower
Correct Answer :
D. Heat rejection is lower
Related Questions
Stirling and Ericsson cycles are
Reversible cycles
Irreversible cycles
Semi-reversible cycles
Quasi-static cycles
The natural solid fuel is
Wood
Coke
Anthracite coal
Pulverised coal
When a gas is heated, change takes place in
Pressure
Volume
Temperature
All of these
The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
Dual combustion cycle
Diesel cycle
Atkinson cycle
Rankine cycle
The columns whose slenderness ratio is less than 80, are known as
Short columns
Long columns
Weak columns
Medium columns
Those substances which have so far not been resolved by any means into other substances of simpler form are called
Elements
Compounds
Atoms
Molecules
The fuel mostly used in steam boilers is
Brown coal
Peat
Coking bituminous coal
Non-coking bituminous coal
The heat and work are mutually convertible. This statement is called __________ law of thermodynamics.
Zeroth
First
Second
Third
One kg of carbon produces __________ kg of carbon dioxide.
3/7
7/3
11/3
3/11
The behaviour of super-heated vapour is similar to that of
Perfect gas
Air
Steam
Ordinary gas
If Th is the torque resisting capacity of a hollow shaft and Ts is that of a solid shaft, of the same material, length and weight. Then,
Th > Ts
Th < Ts
Th = Ts
None of these
Principal planes are planes having
Maximum shear stress
No shear stress
Minimum shear stress
None of the above
The sum of internal energy (U) and the product of pressure and volume (p.v) is known as
Workdone
Entropy
Enthalpy
None of these
Coke is produced
When coal is first dried and then crushed to a fine powder by pulverising machine
From the finely ground coal by moulding under pressure with or without a binding material
When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel
By heating wood with a limited supply of air to a temperature not less than 280°C
Which of the following is an intensive property of a thermodynamic system?
Volume
Temperature
Mass
Energy
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
Of same magnitude as that of bar and applied at the lower end
Half the weight of bar applied at lower end
Half of the square of weight of bar applied at lower end
One fourth of weight of bar applied at lower end
The efficiency of Diesel cycle depends upon
Temperature limits
Pressure ratio
Compression ratio
Cut-off ratio and compression ratio
Which of the following statement is correct according to Clausis statement of second law of thermodynamics?
It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.
It is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source.
It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.
None of the above
A process, in which the gas is heated or expanded in such a way that the product of its pressure and volume remains constant, is called
Isothermal process
Hyperbolic process
Adiabatic process
Polytropic process
The deformation of a bar under its own weight is _________ the deformation, if the same body is subjected to a direct load equal to weight of the body.
Equal to
Half
Double
Quadruple
The work ratio of simple gas turbine cycle depends upon
Maximum cycle temperature
Minimum cycle temperature
Pressure ratio
All of these
One kg of carbon monoxide requires __________ kg of oxygen to produce 11/7 kg of carbon dioxide gas.
4/7
11/4
9/7
All of these
Which of the following cycles has maximum efficiency?
Rankine
Stirling
Carnot
Brayton
Brayton cycle consists' of following four processes
Two isothermals and two isentropic
Two isentropic and two constant volumes
Two isentropic, one constant volume and one constant pressure
Two isentropic and two constant pressures
The tensile strength of the welded joint for double fillet is (where s = Leg or size of the weld, l = Length of weld, and σt = Allowable tensile stress for weld metal)
0.5 s.l.σt
s.l.σt
√2 s.l.σt
2.s.l.σt
The shear force at the centre of a simply supported beam with a gradually varying load from zero at both ends to w per metre at the centre, is
Zero
wl/4
wl/2
wl²/2
In a tensile test on mild steel specimen, the breaking stress as compared to ultimate tensile stress is
More
Less
Same
More/less depending on composition
The heating of a gas at constant pressure is governed by
Boyle's law
Charles' law
Gay-Lussac law
Avogadro's law
The value of modulus of elasticity for mild steel is of the order of
2.1 × 10⁵ kg/cm²
2.1 × 10⁶ kg/cm²
2.1 × 10⁷ kg/cm²
0.1 × 10⁶ kg/cm²
The ideal efficiency of a Brayton cycle without regeneration, with increase in pressure ratio will
Increase
Decrease
Remain unchanged
Increase/decrease depending on application