421. _______________ number determines whether the fluid flow in an open channel is super-critical, critical or sub-critical ?
422. Satellite is a _________________ material?
C. Cemented carbide
D. Non-ferrous cast alloy cutting tool
423. Catalyst used in the catalytic converter employed in automobiles to convert CO into CO2 and for complete oxidation of un-burnt hydrocarbons is___________________?
424. Cascade control is___________________?
A. The continuous adjustment of the set point index of an automatic control loop by a primary (master) controller
B. Useful to control flow from temperature
C. Used when changes in process conditions cause serious upsets in the controlled variable
D. All A, B & C
425. For the irreversible reaction, Ca+ 2C = Ca C2 , Δ H°298 = – 60000 J . mole-1 . If a system initially containing 2 moles of calcium, 3 moles of carbon and 1 mole of calcium carbide is allowed to react to completion, the heat evolved at 298 K will be__________________?
A. 60,000 J
B. 30,000 J
C. 90,000 J
D. 2,40,000 J
426. Hardening of steel is not possible, unless it is heated _________________ critical point ?
A. Between the first & second
B. Above the lowest
C. Above the highest
D. Between the second & third
427. Strain hardening effect in metals subjected to cold working is due to the _______________ mechanism?
428. Atomic _________________ of an element is a whole number ?
429. Which of the following heat treatment processes is usually applied to castings ?
430. A material is capable of resisting softening at high temperature, because of its property termed as____________________?
B. Hot hardness
C. Hot temper
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