1. The ultimate strength of steel in tension in comparison to shear is in the ratio of
(a) 1 : 1
(b) 2:1
(c) 3 : 2
(d) 2 : 3
(e) 1 : 2
Ans: c
2. The pci Tnissible stress for carbon steel under static loading is generally taken as
(a) 2000-3000 kg/pm2
(b) 3000-4000 kg/cm2
(c) 4000-J500 kg/cm2
(d) 7500-10,000 kg/cm2
(e) 10,000-15,000 kg/cm2
Ans: c
3. The property of a material which enables it to resist fracture due to high impact loads is known as
(a) elasticity
(b) endurance
(c) strength
(d) toughness
(e) resilience
Ans: d
4. A hot short metal is
(a) brittle when cold
(b) brittle when hot
(c) brittle under all conditions
(d) ductile at high temperature
(e) hard when hot
Ans: b
5. Guest’s theory of failure is applicable for following type of materials
(a) brittle
(b) ductile
(c) elastic
(d) plastic
(e) tough
Ans: b
6. Rankine’s theory of failure is applicable for following type of materials
(a) brittle
(b) ductile
(c) elastic
(d) plastic
(e) tough
Ans: a
7. If an unsupported uniform cross sectional elastic bar is subjected to a longitudinal impact from a rigid bob moving with velocity v, then a compressive wave of intensity sc is propagated through the bar as follows
(a) vpE
(b) vVvF
(c) WpE/2
(d) IvHpE
(e) none of the above,
where E = modulus of elasticity and p = mass density.
Ans: a
8. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test
(a) Brinell
(b) Rockwell
(c) Vicker
(d) Shore’s sceleroscope
(e) none of the above
Ans: a
9. Resilience of a material is important, when it is subjected to
(a) combined loading
(b) fatigue
(c) thermal stresses
(d) wear and tear
(e) shock loading
Ans: e
10. In the case of an elastic bar fixed at upper end and loaded by a falling weight at lower end, the shock load produced can be decreased by
(a) decreasing the cross-section area of’ bar
(b) increasing the cross-section area of bar
(c) remain unaffected with cross-section area
(d) would depend upon other factors
(e) none of the above
Ans: a
11. .Other method of reducing shock load in the above case can be
(a) to decrease length
(b) to increase length
(c) unaffected by length
(d) other factors would decide same
(e) none of the above
Ans: b
12. If a load W is applied instantaneously on a bar; then the stress induced in bar will
(a) be independent of ratio of mass of load W to mass of bar (y)
(b) increase with increase in y
(c) decrease with decrease in y
(d) depend on other considerations
(e) none of the above
Ans: a
13. Brittle coating technique is used for
(a) determining brittleness
(b) protecting metal against corrosion
(c) protecting metal against wear and tear
(d) experimental stress analysis
(e) non-destructive testing of metals
Ans: d
14. Stress concentration is caused due to
(a) variation in properties of material from point to point in a member
(b) pitting at points or areas at which loads on a member are applied
(c) abrupt change of section
(d) all of the above
(e) none of the above
Ans: d
15. The endurance limit of a material with finished surface in comparison to rough surface is
(a) more
(b) less
(c) same
(d) more or less depending on quantum of load
(e) unpredictable
Ans: a
16. Plastic flow in ductile materials
(a) increases the seriousness of static loading stress concentration
(b) lessens the seriousness of static loading stress concentration
(c) has no effect on it
(d) depends on other considerations
(e) none of the above
Ans: b
17. The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be
(a) same in both cases
(b) 2 times more
(c) 3 times more
(d) 4 times more
(e) unpredictable
Ans: c
18. The fatigue life of a part can be improved by
(a) electroplating
(b) polishing
(c) coating
(d) shot peening
(e) heat treating
Ans: d
19. Stress concentration in static loading is more serious in
(a) ductile materials
(b) brittle materials
(c) equally serious in both cases
(d) depends on other factors
(e) unpredictable
Ans: b
20. Stress concentration in cyclic loading is more serious in
(a) ductile materials
(b) brittle materials
(c) equally serious in both cases
(d) depends on other factors
(e) unpredictable
Ans: a
21. Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to
(a) dynamic loading
(b) static loading
(c) combined static and dynamic loading
(d) completely reversed loading
(e) all of the above
Ans: d
22. Pick up wrong statement. Fatigue strength can be increased by
(a) cold working
(b) shot peening
(c) grinding and lapping surface
(d) hot working
(e) using gradual changes of section
Ans: d
23. Which of the following is not correct procedure to increase the fatigue limit
(a) cold working
(b) shot peening
(c) surface decarburisation
(d) under-stressing
(e) all of the above
Ans: c
24. Coaxing is the procedure of increasing
(a) metal strength by cycling
(b) metal hardness by surface treatment
(c) metal resistance to corrosion by coating
(d) fatigue limit by overstressing the metal by successively increasing loadings
(e) none of the above
Ans: d
25. Which is correct statement ?
Stress concentration in static loading is
(a) very serious in brittle materials and less serious in ductile materials
(b) very serious in ductile materials and less serious in brittle materials
(c) equally serious in both types of materials
(d) seriousness would depend on other factors
(e) none of the above.
Ans: a