FACTOR OF SAFETY MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

FACTOR OF SAFETY

MULTIPLE CHOICE QUESTIONS  

(MCQ) WITH ANSWERS

 

MCQ on factor of safety increases

understanding and clarity. Factor of

safety is extremely important in design of

machine elements. Factor safety takes care

of the uncertainties of all types.

Uncertainties are due to type of load,

the manner of load application and

amount of eccentricity encountered.

Fig. Factor of safety

Sr. No.	Type of equipment	Factor of safety
1.	Aircraft components	1.5 to 2.5
2.	Boilers, Pressure vessels	3.5 to 6
3.	Turbine rotating components	2 to 3
4.	Turbine static components	6 to 8
5.	Structural sheet work in buildings	4 to 6
6.	Structural components in bridges	5 to 7
.7	Bolts, ropes and hooks	8 to 9
8.	Cast iron wheels	20
9.	Heavy duty shafts	10 to 12

1. Factor of safety used under gradually applied load. 

(a) 2 and 4
(b) 4 and 8
(c) 8 and 16
(d) None
(Ans: a)

2. Factor of safety used under suddenly applied load. 

(a) 2 and 4
(b) 4 and 8
(c) 8 and 16
(d) None
(Ans: b)

 3. Factor of safety under impact load is

 
(a) 2 and 4
(b) 4 and 8
(c) 8 and 16
(d) None
(Ans: c)

4. Safety factor for a ductile material is

 
(a) Real stress/unit stress
(b) Ultimate stress/maximum stress
(c) Yield stress/ allowable stress
(d) None
(Ans: c)

  5.  Factor of safety for a brittle material is

(a) Real stress/unit stress
(b) Ultimate stress/allowable stress
(c) Allowable stress/ Yield stress
(d) None
(Ans: b)

6.  Factor of safety accounts for

(a) Uncertainties
(b) Linear displacements
(c) Parabolic displacements
(d) None
(Ans: a)

 7. Other common name of the factor of safety is

(a) Strength factor
(b)Strain factor
(c)Ignorance factor
(d) None
(Ans: c)

8. Under exact analysis of stresses, factor of safety is

(a) More
(b) Less
(c) Zero
(d) None
(Ans: c)

9.  Material cost due to high factor of safety 

(a) Increases
(b) Decreases
(c) No change
(d) None
(Ans: a)

 10. Which elastic theory of failure considers the factor of safety for a brittle material?

(a) Maximum principal stress theory

(b) Maximum shear stress theory

(c) Von Mises theory

(d) None

(Ans: d)

 11. Which theory of elastic failure accounts for factor of safety for a ductile material?

(a) Maximum principal stress theory

(b) Maximum shear stress theory

(c) Maximum principal strain theory

(d) None

(Ans: b)

 12. The factor of safety for a ductile material is 

(a)  σ_yp/σ_allow

(b) σ_ult/σ_allow

(c) σ_ult/σ_yp

_{(d) None}

Ans:(a)

13. Factor of safety in a ductile material is

1. Design stress/working stress

2. Ultimate stress / allowable stress

3. Yield stress/allowable stress

4. None

(Ans: c)

14. In a brittle material, factor of safety is

1. Design stress/working stress

2. Ultimate stress / allowable stress

3. Yield stress/allowable stress

4. None

(Ans: b)

15.  Which theory of elastic failure considers the factor of safety for ductile material?

1.  Principal Stress Theory

2.  Shear Stress Theory

3.  Principal Strain Theory

4. None

(Ans: b)

16. Which theory of elastic failure considers factor of safety for brittle material?

1.   Maximum Principal Stress Theory

2.   Shear Stress Theory (Maximum)

3.  Maximum Shear Strain Energy Theory

4. None

(Ans: a)

17. Large value of factor of safety is

(a) Very good

(b) Good

(c) Bad

(d) None

(Ans: c)

18. What is the FOS for a domestic gas cylinder?

(a) 2 to 4

(b)4 to 6

(c) 6 to 8

(d) None

ANS: (b)

19. What is the factor of safety for a nut?

(a) 3 to 5

(b) 5 to 7

(c) 8 to 9

(d) None

ANS: (c)

20. The factor of safety for a flywheel is

(a) 5

(b) 10

(c) 15

(d) None

ANS: (d)

21. The factor of safety for a flywheel is

(a) 20

(b) 300

(c) 40

(d) None

ANS: (a)