The stress necessary to initiate yielding is
Considerably greater than that necessary to continue it
Considerably lesser than that necessary to continue it
Greater than that necessary to stop it
Lesser than that necessary to stop it
Correct Answer :
A. Considerably greater than that necessary to continue it
Related Questions
The volumetric or molar specific heat at constant pressure is the product of
Molecular mass of the gas and the specific heat at constant volume
Atomic mass of the gas and the gas constant
Molecular mass of the gas and the gas constant
None of the above
Petrol is distilled at
65° to 220°C
220° to 345°C
345° to 470°C
470° to 550°C
A material obeys hooks law up to
Plastic limit
Elastic limit
Yield point
Limit of proportionality
Otto cycle consists of
Two constant volume and two isentropic processes
Two constant pressure and two isentropic processes
Two constant volume and two isothermal processes
One constant pressure, one constant volume and two isentropic processes
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)
Reversed Joule cycle is known as
Carnot cycle
Bell-Coleman cycle
Rankine cycle
Stirling cycle
The entropy of water at 0°C is assumed to be
1
0
-1
10
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
A body is subjected to a direct tensile stress of 300 MPa in one plane accompanied by a simple shear stress of 200 MPa. The maximum shear stress will be
-100 MPa
250 MPa
300 MPa
400 MPa
When a rectangular beam is loaded transversely, the maximum compressive stress is developed on the
Top layer
Bottom layer
Neutral axis
Every cross-section
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 maximum bending moment for the beam shown in the below figure, is
wl²/3√3
wl²/6√3
wl²/9√3
wl²/12√3
The pressure exerted by an ideal gas is ________ of the kinetic energy of all the molecules contained in a unit volume of gas.
One-half
One-third
Two-third
Three-fourth
A bar of copper and steel form a composite system, which is heated to a temperature of 40°C. The stress induced in the copper bar will be
Tensile
Compressive
Shear
Zero
A simply supported beam with a gradually varying load from zero at B and w per unit length at A is shown in the below figure. The shear force at B is equal to
wl/6
wl/3
wl
2wl/3
The section modulus of a circular section about an axis through its C.G., is
πd²/4
πd²/16
πd3/16
πd3/32
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 amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called
Specific heat at constant volume
Specific heat at constant pressure
kilo-Joule
None of these
For the same compression ratio, the efficiency of dual combustion cycle is
Greater than Diesel cycle and less than Otto cycle
Less than Diesel cycle and greater than Otto cycle
Greater than Diesel cycle
Less than Diesel cycle
The value of Poisson's ratio for steel is between
0.01 to 0.1
0.23 to 0.27
0.25 to 0.33
0.4 to 0.6
The principal constituents of a fuel are
Carbon and hydrogen
Oxygen and hydrogen
Sulphur and oxygen
Sulphur and hydrogen
The standard value of atmospheric pressure taken at sea level is
1.013 bar
760 mm of Hg
1013 × 102 N/m2
All of these
In a belt drive, the pulley diameter is doubled, the belt tension and pulley width remaining same. The changes required in key will be
Increase key length
Increase key depth
Increase key width
Double all the dimensions
The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that
Carnot cycle can't work with saturated steam
Heat is supplied to water at temperature below the maximum temperature of the cycle
A Rankine cycle receives heat at two places
Rankine cycle is hypothetical
When the gas is heated at constant pressure, the heat supplied
Increases the internal energy of the gas
Increases the temperature of the gas
Does some external work during expansion
Both (B) and (C)
A concentrated load is one which
Acts at a point on a beam
Spreads non-uniformly over the whole length of a beam
Spreads uniformly over the whole length of a beam
Varies uniformly over the whole length of a beam
Which of the following is an irreversible cycle?
Carnot
Stirling
Ericsson
None of the above
The efficiency of Diesel cycle with decrease in cut-off
Increases
Decreases
First increases and then decreases
First decreases and then increases
The oxygen atom is ________ times heavier than the hydrogen atom.
2
8
16
32
The atomic mass of sulphur is
12
14
16
32