Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by
Conduction
Convection
Radiation
Both 'a' & 'b'
Correct Answer :
C. Radiation
Related Questions
Heating of ferromagnetic materials to a temperature above Curie temperature makes it
Insulator for heat & electricity transmission
Ferritic
Behave like paramagnetic materials
Superconductor
Boiler tube size is specified by its thickness and __________ diameter.
Outside
Inside
Mean
None of these
The refractory lining of the bottom in a basic electric arc furnace is made of
Silica
Alumina
Magnesia
Fireclay
Which of the following is prone to cup and cone fracture?
Cast iron
Soft brass
Round specimen of ductile metal
Flat tensile specimen of ductile metal
Energy to be supplied to the radioactive nucleus for the emission of a neutron is __________ MeV.
0.8
7.8
200
10000
An approximately __________ process exemplifies the flow of a gas through a very long pipe of uniform cross-section.
Adiabatic
Isothermal
Isentropic
Isochoric
__________ of hard alloy and tool steel is done to make it easily machinable.
Case carburising
Tempering
Normalising
Annealing
The main reducing agent in iron blast furnace is
Carbon dioxide
Carbon monoxide
Oxygen
Air
Unit of viscosity in CGS system is
Reynolds number of a fluid flowing in a circular pipe is 10,000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30%?
9,100
13,000
7,000
2,550
__________ is used as a material of construction for the blade of power saw.
Wrought iron
Stainless steel
Mild steel
High speed steel
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
A 2 kg object weighs 1.8 kgf on a spring balance. The value of 'g' at that location in m/sec2 is
8.82
9.81
10.88
0.95
Percentage of differential pressure lost in a Venturimeter with a tapering of 15° may be about
1
10
25
50
Gage pressure within a spherical droplet of a fluid is 'p'. What will be gage pressure within a bubble of the same size & of the same fluid?
p
2 p
0.5 p
0.25 p
__________ is not used as the control rod material in a nuclear reactor.
Cobalt
Hafnium
Cadmium
Boron
As per international norms, the maximum permissible value of noise level in the industrial environment is __________ decibels as measured at a distance of 1.5 metres from the source of noise.
110
85
60
45
Energy of the sun arises mainly from __________ reactions.
Fusion
Fission
Combustion
None of these
Which of the following is a boiler accessory
i.e., not a boiler mounting?
Blow off cock
Feed check valve
Feed water pump
Stop valve
Hot & cold working of material causes its __________ deformation.
Visco-elastic
Isotropic
Elastic
Plastic
The life of a ball bearing is inversely proportional to
(Load)1
(Load)2
(Load)3
(Load)0.33
When the wavelength of incident X-rays increases, the angle of diffraction
Decreases
Increases
Remain constant
Shows no systematic variation
The taper provided on pattern for its easy & clean withdrawal from the mould is termed as the __________ allowance.
Casting
Pattern
Draft
Distortion
Triple point of water is
0°F
492°R
0°K
-273°C
Use of economiser in a boiler plant reduces the fuel consumption for steam generation by about __________ percent.
1
10
30
50
Thermal equivalent of electrical power in practical calculation is __________ kcal/kWh.
746
3000
1000
550
__________ joint is usually used for joining cast iron pipes mostly used for temporary pipelines, where it may be necessary to dismantle & reassemble the pipeline very frequently.
Collar
Flanged
Bell and Spigot
Expansion
Which of the following alloying elements is present in maximum percentage in high speed steel?
Molybdenum
Chromium
Tungsten
Vanadium
Fahrenheit and Centigrade scales have the same readings at
-55°
-40°
-33°
-58°
Dies for wire drawing are generally made of
Mild steel
Stainless steel
Carbides
High carbon steel