SECTION-5

MACHINE DESIGN MCQ

##### Q31. In a transverse double fillet welded lap joint, the allowable tensile stress for the well metal is equal to

(a) 1.414 F/h × l
(b) 0.707 F/h× l
(c) 4.414 F/h× l
(d) 3F/h ×l
where h = Thickness of the plate, l = Length of weld.

Ans:(b) 0.707 F/h× l

##### Q32. In a transverse single fillet welded lap joint, the allowable tensile stress for the weld metal is equal to

(a) 1.414 F/h × l
(b) 0.707 F/h× l
(c) 4.414 F/h× l
(d) 3F/h ×l

Ans:(a) 1.414 F/h × l

##### Q33. When fillet welds are used on one side of the lap joint, a bending moment is introduced because of the eccentricity of the forces. The maximum normal stress due to bending moment is equal to

(a) 1.414 F/h × l
(b) 0.707 F/h× l
(c) 4.414 F/h× l
(d) 3F/h ×l

Ans:(d) 3F/h ×l

##### Q34. When fillet welds are used on one side of the lap joint, a bending moment is introduced because of the eccentricity of the forces, the resultant stress at the root of the weld is equal to

(a) 1.414 F/h × l
(b) 0.707 F/h× l
(c) 4.414 F/h× l
(d) 3F/h ×l

Ans:(c) 4.414 F/h× l

##### Q35. The diameter ‘d’ of the rivet for the given thickness ‘t’ of the plate and to take up a given load F is given by

(a) d = 1.91 $\sqrt{t}$  when d and t are in mm

(b) d = 6 $\sqrt{t}$ when d and t are in cm

(c) both (a) and (b)
(d) none of the above.

Ans:(d) none of the above.

##### Q36. Unwin’s empirical formula is used to find

(a) pitch of a riveted joint
(b) diameter of the rivet hole, when thickness of the plates is less than 8 mm
(c) diameter of the rivet hole, when thickness of the plate is more than 8 mm
(d) none of the above.

Ans:(c) diameter of the rivet hole, when thickness of the plate is more than 8 mm

##### Q37. In Lozenge joint

(a) diamond riveting is used
(b) number of rivets in each row is the same
(c) number of rivets in each row goes no decreasing as we proceed from the outermost row to innermost row
(d) none of the above.

Ans:(a) diamond riveting is used

##### Q38. Two plates are joined by a lap joint. The pull required to crush the rivet per pitch length is equal to

(a) n × d × t × σc
(b) π(d – t) × t × σc
$\text { (c) } n \times\left(\frac{\pi}{4} d^{2}-d t\right) \sigma_{c}$

$\text { (d) } n \times \frac{\pi}{4} d^{2} \times \sigma_{c} \text {. }$

where σc = Permissible crushing stress, n = Number of rivets per pitch length under crushing,
and d = Diameter of rivet.

Ans:(a) n × d × t × σc

##### Q39. Which of the following screw thread is used for power transmission in either direction?

(d) All of the above.

##### Q40. Efficiency of a square threaded screw, neglecting collar friction is given by

(a) tan α/tan φ
(b) tan α/tan (α+φ)
(c) tan φ/tan α
(d) tan φ/tan (α+φ)
where α = Helix angle, and φ = Angle of friction.

Ans:(b) tan α/tan (α+φ)

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##### Read More Sections of Machine Design

Each section contains maximum 80 Questions. To practice more questions visit other sections.

Machine Design MCQ – Section-1

Machine Design MCQ – Section-2

Machine Design MCQ – Section-3

Machine Design MCQ – Section-4

Machine Design MCQ – Section-5

Machine Design MCQ – Section-6

Machine Design MCQ – Section-7