1020235110 – ELEMENTS OF MACHINE DESIGN STUDY MATERIALS

 

20 MARKS MCQ TEST LINK MCQ TEST LINK

 

 

1. The preferred number series used in engineering design follows which
a) Arithmetic
 b) Geometric
c) Harmonic
d) Random

👉 Explanation: Engineering preferred number series (like R5, R10) are based on geometric progression for standardization of sizes.

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2. The maximum distortion energy theory is also known as:
 a) Von Mises theory
b) Rankine theory
c) Tresca theory
d) Mohr's theory

👉 Explanation: Von Mises theory = Maximum distortion energy theory → used for ductile materials.

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3. The factor of safety for brittle materials is usually ______ than for ductile materials.
 a) Higher
b) Lower
c) Equal
d) Unpredictable

👉 Explanation: Brittle materials fail suddenly → so higher safety factor is used.

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4. The maximum distortion energy theory is best suited for:
a) Brittle materials
 b) Ductile materials
c) Composites
d) Ceramics

👉 Explanation: Von Mises (Distortion energy) applies to ductile materials like steel.

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5. Flange couplings are classified as:
a) Flexible couplings
 b) Rigid couplings
c) Fluid couplings
d) Magnetic couplings

👉 Explanation: Flange coupling rigidly connects shafts — no flexibility for misalignment.

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6. In a pin-type flexible coupling, flexibility is achieved by:
a) Increase speed
b) Reduce power loss
 c) Compensate misalignment
d) Lower cost

👉 Explanation: Pins with rubber bushes allow slight misalignment between shafts.

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7. Which coupling type would be most suitable for connecting shafts with angular misalignment?
a) Rigid flange coupling
b) Marine coupling
 c) Universal coupling
d) Protected flange coupling

👉 Explanation: Universal joint allows angular motion and misalignment between shafts.

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8. The main advantage of marine couplings is:
 a) Corrosion resistance
b) High speed capacity
c) Low maintenance
d) Light weight

👉 Explanation: Marine couplings are designed to resist sea water corrosion.

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9. What does the designation 'B75' for a V-belt typically indicate?
a) Belt type 'B' and 75 cm inside length
 b) Belt type 'B' and 75 inches pitch length
c) Belt type 'B' and 75 mm width tension
d) Belt type 'B' and a maximum of 75 N

👉 Explanation: In V-belts, number = pitch length in inches.

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10. When designing a V-belt drive using manufacturer’s catalogues, the first step is to determine the:
 a) Design power (Service factor × Power)
b) Center distance
c) Belt length
d) Number of belts

👉 Explanation: Design starts with design power, considering service conditions.

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11. The 'angle of contact' for the smaller pulley in an open belt drive is:
a) Always 180°
 c) Always <180°
b) Always >180°
d) Independent of pulley diameters

👉 Explanation: In open belt drive, belt leaves pulley tangentially → less than 180°.

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12. A designer needs a belt for 15 kW. Manufacturer’s rating per belt = 4.2 kW. The minimum number of belts is:
a) 3
 b) 5
c) 4
d) 7

👉 Explanation: 15 ÷ 4.2 = 3.57 → take next higher integer = 5 belts (for safety).

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13. A bearing designed for axial forces is called:
 a) Thrust bearing
b) Radial bearing
c) Journal bearing
d) Roller bearing

👉 Explanation: Thrust bearing → supports axial (end) loads.

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14. In ball bearing code “6205”, bore size is indicated by:
a) First digit
b) Middle digit
c) Prefix letters
 d) Last two digits

👉 Explanation: For bearing codes, bore = last two digits × 5 mm → 05 → 25 mm bore.

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15. Journal bearing, D = 50 mm, L = 50 mm, W = 6 kN. Find bearing pressure.
 a) 2.55 MPa
b) 2.30 MPa
c) 2.0 MPa
d) 2.40 MPa

👉 Explanation:
Bearing pressure p=WL×D=60000.05×0.05=2.55 MPap = \frac{W}{L \times D} = \frac{6000}{0.05 \times 0.05} = 2.55 \text{ MPa}p=L×DW​=0.05×0.056000​=2.55 MPa

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16. The coefficient of friction in properly lubricated journal bearings is:
 a) 0.001–0.01
b) 0.1–0.3
c) 0.5–0.7
d) 0.8–1.0

👉 Explanation: With lubrication, friction is very low (around 0.001–0.01).

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17. The primary role of CAD in design is to:
a) Replace engineers
 b) Assist in design process
c) Manufacture products
d) Market products

👉 Explanation: CAD = Computer-Aided Design, helps engineers design accurately.

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18. Value Engineering focuses on:
a) Increasing cost
b) Maintaining function
c) Reducing quality
d) Extending timeline

👉 Explanation: Value engineering = reduce cost without affecting function/quality.

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19. The main advantage of solid modeling over wireframe is:
a) Lower cost
 b) Complete representation
c) Faster computation
d) Simpler algorithms

👉 Explanation: Solid models show volume, mass & surface, unlike wireframe.

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20. Which modeling approach uses primitives and Boolean operations?
a) B-Rep
 b) CSG
c) Wireframe
d) Surface

👉 Explanation: Constructive Solid Geometry (CSG) uses Boolean ops (union, subtract, intersect) with primitives like cube, cylinder.

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✅ Final Answer Key Summary:
1-b | 2-a | 3-a | 4-b | 5-b | 6-c | 7-c | 8-a | 9-b | 10-a | 11-c | 12-b | 13-a | 14-d | 15-a | 16-a | 17-b | 18-b | 19-b | 20-b