Alcohols are not suitable as diesel engine fuel because the cetane number of alcohols is
Very low which prevents their ignition by compression
Very high which prevents their ignition by compression
Zero
None of these
Correct Answer :
A. Very low which prevents their ignition by compression
Related Questions
Induced draft fans provided in large thermal power plant boilers have __________ blades.
Forward curved
Backward curved
Double curved
Radial or straight
Percentage of argon (by volume) in dry atmospheric air is about
0.09
0.3
0.57
0.94
Which one is neutral in character?
N2O4
N2O
N2O5
N2O3
In multipass welds, shot peening is done after each pass to
Close the surface porosity
Break the continuity of columnar grains
Flatten the weldment
Introduce texture in the weld
'Amortization' in respect of financial obligation of a company means the
Liquidation of financial obligations on instalment basis
Commitment of financial obligation on priority
Liquidation of all the obsolete equipments of the company
Modernisation of the plant equipments
Factor of safety is the ratio of the __________ stress to the working stress.
Tensile
Compressive
Yield
Bearing
Holes for riveting purposes should be preferably made by
Cutting torch
Drilling
Punching
None of these
The ability of tool steel to resist softening at high temperatures is termed as __________ hardness.
Red
Extended
Super
Extreme
Which of the following materials has the least scrap value?
Aluminium
Stainless steel
Brass
Copper
Pick out the wrong statement.
Cold cracking of a weld is due to the presence of hydrogen gas in the weld
True stress is given by, σ = σE (1 + εE), where σE and εE are engineering stress and engineering strain respectively
Phosphorous can be easily recovered in the iron blast furnace
High residual stress at the surface is beneficial for fatigue properties of a material
The units of the rate constant for a second order reaction are
Fire refining process is employed in case of
Tin
Copper
Zinc
Aluminium
Fine grained steels have
High brittleness
Higher tendency to distort
High ductility
None of these
When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the
Partial pressure of water vapour is less than the total pressure
Humidity is < 100% & dew point temperature of air has not reached
Dew point temperature of air has not reached & air is not saturated fully
Air is fully saturated
Runge-Kutta method is used to solve a/an
Ordinary differential equation of nth order
Simultaneous non-linear equation
Linear differential equation
None of these
Hot & cold working of material causes its __________ deformation.
Visco-elastic
Isotropic
Elastic
Plastic
Lead is poured into the joint between two- __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
Dryness fraction of dry steam is
0
∞
1
0.5
Electrical conductivities of semi-conductors are of the order of __________ ohm/cm.
10-3
103
10-15
1015
Fatigue resistance of a material is measured by the
Elastic limit
Ultimate tensile strength
Young's modulus
Endurance limit
Air-petrol ratio in an automotive petrol engine is around
14 : 1
22 : 1
25 : 1
4 : 1
Cascade control is
The continuous adjustment of the set point index of an automatic control loop by a primary (master) controller
Used when changes in process conditions cause serious upsets in the controlled variable
Useful to control flow from temperature
All 'a', 'b' & 'c'
Which of the following are considered applications of ultrasonic testing?
Determination of elastic constant
Detection of defects in metal
Measurement of material thickness
None of the above
In a totally irreversible isothermal expansion process for an ideal gas, ΔE = 0, ΔH = 0. Then ΔQ and ΔS will be
ΔQ = 0, ΔS=0
ΔQ = 0, ΔS = +ve
ΔQ = 0, ΔS = -ve
ΔQ = +ve, ΔS= +ve
A solid aluminium ball, when quenched in a water bath maintained at 40°C, cools down from 550°C to 450°C in 20 seconds. The expected temperature of the ball after next 20 seconds may be about __________ °C.
370
340
320
300
More than 95% of __________ is present in corundum.
SiO2
Al2O3
CaSiO2
MgO
Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of
Grashoff number
Grashoff number & Reynolds number
Reynolds number
Grashoff number & Prandtl number
For a small scale toy factory, the fixed cost per month is Rs. 5000/-. The variable cost per toy is Rs. 20 and sales price is Rs. 30 per toy. The break even production per month will be __________ toys.
250
500
1000
3000
__________ is the process used for setting up compressive stresses in the surface of a metal to improve its fatigue strength.
Lancing
Shot peening
Slugging
Spinning
Pick out the correct statement about the condensation.
Filmwise condensation gives a lower heat transfer rate than the dropwise condensation
Suitable coating or vapour additive is used to promote film wise condensation
If a condensing liquid does not wet the surface dropwise, even then condensation will take place on it
Reynolds number of condensing liquid is based on its mass flow rate