421. _______________ number determines whether the fluid flow in an open channel is super-critical, critical or sub-critical ?
A. Reynolds
B. Mach
C. Froude
D. Weber

422. Satellite is a _________________ material?
A. Ceramic
B. Ferrous
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___________________?
A. Cobalt
B. Nickel
C. Vanadium
D. Platinum

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?
A. Fracture
B. Slip
C. Winning
D. Dislocation

428. Atomic _________________ of an element is a whole number ?
A. Volume
B. Number
C. Weight
D. Radius

429. Which of the following heat treatment processes is usually applied to castings ?
A. Annealing
B. Tempering
C. Normalising
D. Carburising

430. A material is capable of resisting softening at high temperature, because of its property termed as____________________?
A. Fatigue
B. Hot hardness
C. Hot temper
D. Creep

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