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)
Correct Answer :
D. Both (B) and (C)
Related Questions
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 efficiency of the dual combustion cycle for the same compression ratio is __________ Diesel cycle.
Greater than
Less than
Equal to
None of these
When a body is subjected to two equal and opposite pushes, as a result of which the body tends to reduce its length, then
The stress and strain induced is compressive
The stress and strain induced is tensile
Both A and B is correct
None of these
Workdone in a free expansion process is
Zero
Minimum
Maximum
Positive
If the depth is kept constant for a beam of uniform strength, then its width will vary in proportional to
Bending moment (i.e. M)
Bending moment² (i.e. M²)
Bending moment³ (i.e. M³)
Bending moment⁴ (i.e. M⁴)
In an irreversible process, there is a
Loss of heat
No loss of heat
Gain of heat
No gain of heat
The strain energy stored in a body due to suddenly applied load compared to when it is applied gradually is
Same
Twice
Four times
Eight times
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
The efficiency of the Carnot cycle may be increased by
Increasing the highest temperature
Decreasing the highest temperature
Increasing the lowest temperature
Keeping the lowest temperature constant
The point of contraflexure is a point where
Shear force changes sign
Bending moment changes sign
Shear force is maximum
Bending moment is maximum
In an extensive property of a thermodynamic system
Extensive heat is transferred
Extensive work is done
Extensive energy is utilised
None of these
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 point of contra flexure is a point where
Shear force changes sign
Shear force is maximum
Bending moment changes sign
Bending moment is maximum
When gas is heated at constant pressure, the heat supplied is utilised in
Increasing the internal energy of gas
Doing some external work
Increasing the internal energy of gas and also for doing some external work
None of the above
The stress developed in a material at breaking point in extension is called
Breaking stress
Fracture stress
Yield point stress
Ultimate tensile stress
Select the correct statement as per Charles' law
p.v = constant, if T is kept constant
v/T = constant, if p is kept constant
p/T = constant, if v is kept constant
T/p = constant, if v is kept constant
One kg of hydrogen requires 8 kg of oxygen and produces
1 kg of water
7 kg of water
8 kg of water
9 kg of water
Which of the following materials is most elastic?
Rubber
Plastic
Brass
Steel
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
During which of the following process does heat rejection takes place in Carnot cycle?
Isothermal expansion
Isentropic expansion
Isothermal compression
Isentropic compression
The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner, is known as
Enthalpy
Internal energy
Entropy
External energy
Modulus of rigidity may be defined as the ratio of
Linear stress to lateral strain
Lateral strain to linear strain
Linear stress to linear strain
Shear stress to shear strain
The variables which control the physical properties of a perfect gas are
Pressure exerted by the gas
Volume occupied by the gas
Temperature of the gas
All of these
The air standard efficiency of an Otto cycle is given by (where r = Compression ratio, and γ = Ratio of specific heats)
1 - rγ - 1
1 + rγ - 1
1 - (1/ rγ - 1)
1 + (1/ rγ - 1)
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
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.
1/27th
1/93th
1/173th
1/273th
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]
If Kh is the torque resisting capacity of a hollow shaft and Ks is that of a solid shaft, of the same material, length and weight. Then,
Kh > Ks
Kh < Ks
Kh = Ks
None of these
A material obeys hooks law up to
Plastic limit
Elastic limit
Yield point
Limit of proportionality
The compression ratio for petrol engines is
3 to 6
5 to 8
15 to 20
20 to 30