The efficiency of Diesel cycle approaches to Otto cycle efficiency when
Cut-off is increased
Cut-off is decreased
Cut-off is zero
Cut-off is constant
Correct Answer :
C. Cut-off is zero
Related Questions
In the tensile test, the phenomenon of slow extension of the material, i. e. stress increasing with the time at a constant load is called
Creeping
Yielding
Breaking
Plasticity
A shaft revolving at ω rad/s transmits torque (T) in Nm. The power developed is
T.ω watts
2π. T.ω watts
2π. T.ω/75 watts
2π. T.ω/4500 watts
One kg of carbon requires 4/3 kg of oxygen and produces __________ kg of carbon monoxide gas.
8/3
11/3
11/7
7/3
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)
t
2t
4t
8t
If both Stirling and Carnot cycles operate within the same temperature limits, then efficiency of Stirling cycle as compared to Carnot cycle
More
Less
Equal
Depends on other factors
The energy stored in a body when strained within elastic limit is known as
Resilience
Proof resilience
Strain energy
Impact energy
When it is indicated that a member is elastic, it means that when force is applied, it will
Not deform
Be safest
Stretch
Not stretch
The value of specific heat at constant pressure (cp) is __________ that of at constant volume (cv).
Less than
Equal to
More than
None of these
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.
Change
Do not change
Both (A) and (B)
None of these
Relation between cp and cv is given by (where cp = Specific heat at constant pressure, cv = Specific heat at constant volume, γ = cp/cv, known as adiabatic index, and R = Gas constant)
cv/ cp =R
cp - cv = R
cv = R/ γ-1
Both (B) and (C)
Kerosene is distilled at
65° to 220°C
220° to 345°C
345° to 470°C
470° to 550°C
When a body is subjected to biaxial stress i.e. direct stresses (σx) and (σy) in two mutually perpendicular planes accompanied by a simple shear stress (τxy), then minimum normal stress is
(σx + σy)/2 + (1/2) × √[(σx - σy)² + 4 τ²xy]
(σx + σy)/2 - (1/2) × √[(σx - σy)² + 4 τ²xy]
(σx - σy)/2 + (1/2) × √[(σx + σy)² + 4 τ²xy]
(σx - σy)/2 - (1/2) × √[(σx + σy)² + 4 τ²xy]
A thin cylindrical shell of diameter (D) and thickness (t) is subjected to an internal pressure (p). The ratio of longitudinal strain to volumetric strain is
(m - 1)/ (2m - 1)
(2m - 1)/ (m - 1)
(m - 2)/ (3m - 4)
(m - 2)/ (5m - 4)
The rivets are used for __________ fastenings.
Permanent
Temporary
Semi-permanent
None of these
According to Kelvin-Planck's statement, a perpetual motion of the __________ is impossible.
First kind
Second kind
Third kind
None of these
An adiabatic process is one in which
No heat enters or leaves the gas
The temperature of the gas changes
The change in internal energy is equal to the mechanical workdone
All of the above
The ratio of the largest load in a test to the original cross-sectional area of the test piece is called
Elastic limit
Yield stress
Ultimate stress
Breaking stress
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 calorific value of gaseous fuel is expressed in
kJ
kJ/kg
kJ/m2
kJ/m3
The ratio of lateral strain to the linear strain within elastic limit is known as
Young's modulus
Bulk modulus
Modulus of rigidity
Poisson's ratio
The absolute zero temperature is taken as
237°C
-273°C
-237°C
273°C
For the same compression ratio, the efficiency of Diesel cycle is __________ Otto cycle.
Greater than
Less than
Equal to
None of these
The extremeties of any diameter on Mohr's circle represent
Principal stresses
Normal stresses on planes at 45°
Shear stresses on planes at 45°
Normal and shear stresses on a plane
Which of the following statement is correct?
The stress is the pressure per unit area
The strain is expressed in mm
Hook's law holds good upto the breaking point
Stress is directly proportional to strain within elastic limit
Two shafts 'A' and 'B' transmit the same power. The speed of shaft 'A' is 250 r.p.m. and that of shaft 'B' is 300 r.p.m.
The shaft 'B' has the greater diameter
The shaft 'A' has the greater diameter
Both are of same diameter
None of these
The intensity of stress which causes unit strain is called
Unit mass
Modulus of rigidity
Bulk modulus
Modulus of Elasticity
The stress at which extension of the material takes place more quickly as compared to the increase in load is called
Elastic point of the material
Plastic point of the material
Breaking point of the material
Yielding point of the material
If percentage reduction in area of a certain specimen made of material 'A' under tensile test is 60% and the percentage reduction in area of a specimen with same dimensions made of material 'B' is 40%, then
The material A is more ductile than material B
The material B is more ductile than material A
The ductility of material A and B is equal
The material A is brittle and material B is ductile
A column is said to be a short column, when
Its length is very small
Its cross-sectional area is small
The ratio of its length to the least radius of gyration is less than 80
The ratio of its length to the least radius of gyration is more than 80
The efficiency and work ratio of a simple gas turbine cycle are
Low
Very low
High
Very high