1.Explain the difference between ferrite, austenite and graphite ? Ans: Ferrite is the solid solution of carbon and other constituents in alpha-iron. It is soft, ductile and relatively weak. Austenite is the solid solution of carbon and other constituents in gamma-iron. It exists in ordinary steels at elevated temperatures, but it is also found at…
1.For which parts the Wahl factor and Lewis form factor used ? Ans: For springs and gears respectively. 2.How oxygen can be removed from steel during melting? What are fully killed steels ? Ans: Oxygen can be removed by adding elements such as manganese, silicon or aluminium which, because of their high affinity for oxygen,…
1.What does thermal diffusivity of metals signify. Ans: Thermal diffusivity is associated with the speed of propagation of heat into solids during changes in temperature with time. 2.For conduction of heat, the instantaneous rate of heat flow is product of three factors. What are these ? Ans: (i) Area of the section of the heat flow…
1.Which element is added in steel to increase resistance to corrosion ? Ans: Chromium. 2.Whether individual components in composite materials retain their characteristics or not? Ans: yes. 3.An elastomer is a polymer when its percentage elongation rate is ? Ans: Greater than 100%. 4.If percentage elongation of a material is more than 200%, it is…
1.What is the difference between isotropic and anisotropic materials ? Ans: If a material exhibits same mechanical properties regardless of loading direction, it is isotropic, e.g., homogeneous cast materials. Materials lacking this property are anisotropic. 2.What are orthotropic materials ? Ans: It is a special class of anisotropic materials which can be described by giving…
1.Which reactor produces more fissionable material than it consumes ? Ans: Breeder reactor. 2.Which reactor uses natural uranium as fuel ? Ans: Gas cooled reacator. 3.Which reactor uses heavy water as moderator ? Ans: CANDU. 4.Which reactor requires no moderator ? Ans: Breeder reactor. 5.Which reactor uses primary coolant as fluoride salts of lithium, beryllium,…
1.How the analyses and calorific values of fuels can be reported ? Ans: It may be reported as (a) as received or fired (wet) basis (b ) dry or moisture free basis © combustible or ash and moisture free basis 2.What is the difference between nuclear fission and fission chain reaction. Ans: The process of…
1.Which reactor has no moderator ? Ans: Fast breeder reactor. 2.What are thermal neutrons ? Ans: Thermal neutrons are slow neutrons (having energy below 1 eV) which are in thermal equilibrium with their surroundings. 3.What is big advantage of fast breeder reactor ? Ans: It has rapid self breeding of fissile fuel during the operation…
1.How you can define coal ? Ans: Coal is a naturally occurring hydrocarbon that consists of the fossilised remains of buried plant debris that have undergone progressive physical and chemical alteration, called coalification, in the course of geologic time. 2.Which pollutant is major greenhouse gas and what is its effect ? Ans: CO is major…
1.Why rockets using liquid hydrogen have higher specific impulse compared to liquid hydrocarbon ? Ans: Liquid hydrogen has higher burning velocity. 2.Why axial flow compressor is preferred for gas turbines for aeroplanes ? Ans: Because it has low frontal area. 3.What is the effect of inter cooling in gas turbines ? Ans: It decreases thermal…