SECTION-3
ENGINEERING MATERIAL OBJECTIVE QUESTIONS/MCQ
 
Q21. If two dissimilar metals are joined and this junction is then heated, a small voltage in the millivolt range is produced. This effect is known as
(a) ferro-electric effect 
(b) piezo-electric effect 
(c) pyroelectric effect 
(d) thermo-electric effect. 
Ans: (d) thermo-electric effect.
Q22. A natural crystal of tourmaline acquires an electric charge when heated. This effect is known as
(a) ferro-electric effect 
(b) piezo-electric effect 
(c) pyroelectric effect 
(d) thermo-electric effect.
Ans: (b) piezo-electric effect
Q23. The expression ‘VI tan δ’ represents
(a) loss factor 
(b) dissipation factor 
(c) dielectric power loss 
(d) none of the above. 
Ans: (c) dielectric power loss
Q24. In the above expression ‘tan δ’ is known as
(a) loss factor 
(b) dissipation factor 
(c) dielectric power loss 
(d) none of the above.
Ans(d) none of the above.:
Q25. The conductivity of an extrinsic semi-conductor
(a) decreases with temperature 
(b) increases with temperature 
(c) remains constant 
(d) first decreases then increases. 
Ans: (b) increases with temperature
Q26. Pearlite is obtained when steel is
(a) quenched in oil 
(b) cooled in still air 
(c) slowly cooled in furnace 
(d) quenched in water. 
Ans: (c) slowly cooled in furnace
Q27. Sorbite is obtained when steel is
(a) quenched in oil 
(b) cooled in still air 
(c) slowly cooled in furnace 
(d) quenched in water. 
Ans: (b) cooled in still air
Q28. A circular is obtained when steel is
(a) quenched in oil 
(b) cooled in still air 
(c) slowly cooled in furnace 
(d) quenched in water.
Ans: (d) quenched in water.
Q29. In case of flame hardening, depth of the hardened zone depends upon
(a) flame intensity 
(b) heating time 
(c) carbon contents 
(d) only (a) and (b). 
Ans: (d) only (a) and (b).
Q30. Choose the wrong statement
(a) In flame hardening it is difficult to produce hardened zones less than 1.5 mm in depth. 
(b) In case of induction hardening, the depth of hardening is controlled by controlling voltage. 
(c) Induction hardening cannot be applied to steels having carbon less than 0.4%. 
(d) In case of nitriding, the distortion or crack formation is maximum
Ans: (d) In case of nitriding, the distortion or crack formation is maximum
 
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Each section contains maximum 80 Questions. To practice more questions visit other sections.
 
Engineering Material Objective Questions – Section-1
 
Engineering Material Objective Questions – Section-2
 
Engineering Material Objective Questions – Section-3
 
Engineering Material Objective Questions – Section-4
 
Engineering Material Objective Questions – Section-5
 
 

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