### Multiple Choice Questions and Answers (MCQs) on Machine Design

01. The ratio of belt tensions (P1/P2) considering centrifugal force in flat belt is given by

(A) (P1 – mv²)/ (P2 – mv²) = eᶠα
(B) P1 /P2 = eᶠα
(C) P1 / P2 = e–ᶠα
(D) (P1 – mv²)/ (P2 – mv²) = e–ᶠα

Where m = mass of belt per metre (kg/m)
v = belt velocity (m/s)
f = coefficient of friction
a = angle of wrap (radians)

Answer: Option A

02. 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

Answer: Option C

03. In radial cams, the follower moves

(A) In a direction parallel to the cam axis
(B) In a direction perpendicular to the cam axis
(C) In any direction irrespective of cam axis
(D) Along the cam axis

Answer: Option B

04. The permissible stress for carbon steel under static loading is generally taken as

(A) 2000-3000 kg/m²
(B) 3000-4000 kg/cm²
(C) 4000-4500 kg/cm²
(D) 7500-10,000 kg/cm²

Answer: Option C

05. 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

Answer: Option D

06. In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because

(A) Belts are available in sets
(B) Only one belt cannot be fitted with other used belts
(C) The new belt will carry more than its share and result in short life
(D) New and old belts will cause vibrations

Answer: Option C

07. A hot short metal is

(A) Brittle when cold
(B) Brittle when hot
(C) Brittle under all conditions
(D) Ductile at high temperature

Answer: Option B

08. In case of pressure vessels having closed ends, the fluid pressure induces

(A) Longitudinal stress
(B) Shear stress
(C) Circumferential stress
(D) None of these

Answer: Option D

09. Guest’s theory of failure is applicable for following type of materials

(A) Brittle
(B) Ductile
(C) Elastic
(D) Plastic

Answer: Option B

10. A V-belt designated as B 4430 LP has

(A) 4430 mm as diameter of small pulley
(B) 4430 mm as nominal pitch length
(C) 4430 mm as diameter of large pulley
(D) 4430 mm as centre distance between pulleys

Answer: Option B

11. Rankine’s theory of failure is applicable for following type of materials

(A) Brittle
(B) Ductile
(C) Elastic
(D) Plastic

Answer: Option A

12. Screws used for power transmission should have

(A) Very fine threads
(B) High efficiency
(C) Low efficiency
(D) Strong teeth

Answer: Option B

13. The value of stress concentration factor depends upon

(A) Material and geometry of the part
(B) Geometry of the part
(C) Material of the part
(D) None of these

Answer: Option A

14. Tensile strength of a mild steel specimen can be roughly predicted from following hardness test

(A) Brinell
(B) Rockwell
(C) Vickers
(D) None of the above

Answer: Option A

15. Resilience of a material is important, when it is subjected to

(A) Combined loading
(B) Fatigue
(C) Thermal stresses
(D) Shock loading

Answer: Option D

16. The sleeve or muff coupling is designed as a

(A) Dun cylinder
(B) Hollow shaft
(C) Solid shaft
(D) Thick cylinder

Answer: Option B

17. In a flange coupling, the flanges are coupled together by means of

(A) Bolts and nuts
(B) Studs
(C) Headless taper bolts
(D) None of these

Answer: Option A

18. 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

Answer: Option A

19. According to Indian standard specifications, 100 H6/g5 means that the

(A) Basic size is 100 mm
(B) Actual size is 100 mm
(C) Difference between the actual size and basic size is 100 mm
(D) None of the above

Answer: Option A

20. The power transmitted by the belt drive can be increased by

(A) Increasing the initial tension in the belt
(B) Dressing the belt to increase the coefficient of friction
(C) Increasing wrap angle by using idler pulley
(D) All of the above methods

Answer: Option D

21. Surface endurance limit of gear material is dependent upon its

(A) Elastic strength
(B) Yield strength
(C) Brinell hardness number
(D) Toughness

Answer: Option C

22. When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as

(A) Crown bevel gears
(B) Angular bevel gears
(C) Mitre gears
(D) Internal bevel gears

Answer: Option A

23. 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

Answer: Option D

24. 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

Answer: Option D

25. 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

Answer: Option A