| 1. |
Stressed parts are always kept in tension. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: cast iron has more compressive strength. | |
| 2. |
Which process allows controlling grain structure of the product? |
| A. | casting |
| B. | forging |
| C. | none of the mentioned |
| D. | die casting |
| Answer» B. forging | |
| Explanation: in casting metal is in fluid state and hence impossible to control the grain structure. | |
| 3. |
Cast surfaces have good finishing. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: cavity is surrounded by sand and hence not good finish is obtained. | |
| 4. |
In forging, metal is in which of the following stage? |
| A. | elastic |
| B. | plastic |
| C. | can be in any stage |
| D. | rigid |
| Answer» B. plastic | |
| Explanation: forging is the working of metal in plastic range. | |
| 5. |
Among casting, forging and forging which has the slowest rate of production? |
| A. | casting |
| B. | forging |
| C. | machining |
| D. | all have equal rate of production |
| Answer» C. machining | |
| Explanation: machining each part is very time consuming. | |
| 6. |
In manual assembly, cost of screw is higher than the cost of driving a screw. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: generally manufacturing screw is cheaper than driving it. | |
| 7. |
Maximum carbon content in welding is usually limited to |
| A. | 0.22% |
| B. | 0.8% |
| C. | 1.5% |
| D. | 2% |
| Answer» A. 0.22% | |
| Explanation: with increase of carbon, welding becomes difficult as weld becomes susceptible to cracks. | |
| 8. |
Why tolerances are given to the parts? |
| A. | because it’s impossible to make perfect settings |
| B. | to reduce weight of the component |
| C. | to reduce cost of the assembly |
| D. | to reduce amount of material used |
| Answer» A. because it’s impossible to make perfect settings | |
| Explanation: tolerances are provided to the parts because variations in the material properties introduce errors and production machines themselves have inherent inaccuracies. another reason to introduce tolerance is that it is not possible to make perfect settings by operator so some tolerances are provided. | |
| 9. |
What is bilateral tolerance? |
| A. | total tolerance is in 1 direction only |
| B. | total tolerance is in both the directions |
| C. | may or may not be in one direction |
| D. | tolerance provided all over the component body |
| Answer» B. total tolerance is in both the directions | |
| Explanation: total tolerance is specified on both the sides of the basic dimension. this usually have + and – tolerance of equal amount. | |
| 10. |
What is mean clearance? |
| A. | maximum size of hole minus maximum size of shaft |
| B. | minimum size of hole minus minimum size of shaft |
| C. | mean size of hole minus mean size of shaft |
| D. | average of both size of shaft and hole |
| Answer» C. mean size of hole minus mean size of shaft | |
| Explanation: statistical approach allows wider tolerances compared to complete interchangeability approach. methods used by statistical approach are usually permits cheaper production. mean clearance is equal to (mean size of hole – mean size of shaft). | |
| 11. |
Which of the following is incorrect about tolerances? |
| A. | too loose tolerance results in less cost |
| B. | tolerance is a compromise between accuracy and ability |
| C. | too tight tolerance may result in excessive cost |
| D. | fit between mating components is decided by functional requirements |
| Answer» A. too loose tolerance results in less cost | |
| Explanation: loose tolerance results in increase in cost, assembly problems and poor performance of the product. tight tolerance results in unnecessary machining and inspection time. | |
| 12. |
Quality control charts doesn’t depend on which factor? |
| A. | normal distribution |
| B. | random sampling |
| C. | independence between samples |
| D. | binomial distribution |
| Answer» D. binomial distribution | |
| Explanation: in establishing of realistic specifications, control charts are considered as a good guide for the design office. quality | |
| 13. |
If a clearance fit is present between shaft and hole, what is the tolerance on shaft or hole for a complete interchangeable approach? |
| A. | ½ of maximum clearance – ½ of minimum clearance |
| B. | ¼ of maximum clearance – ¼ of minimum clearance |
| C. | maximum clearance – minimum clearance |
| D. | ¾ of maximum clearance – ¾ of minimum clearance |
| Answer» A. ½ of maximum clearance – ½ of minimum clearance | |
| Explanation: there are two approaches for deciding of tolerances and shafts i.e. statistical and complete interchangeable approach. there is no risk is taken about a single non-conforming assembly in complete interchangeable approach. | |
| 14. |
A beam is said to be of uniform strength, if |
| A. | b.m. is same throughout the beam |
| B. | shear stress is the same through the beam |
| C. | deflection is the same throughout the beam |
| D. | bending stress is the same at every section along its longitudinal axis |
| Answer» D. bending stress is the same at every section along its longitudinal axis | |
| Explanation: beam is said to be uniform strength if at every section along its longitudinal axis, the bending stress is same. | |
| 15. |
Stress in a beam due to simple bending is |
| A. | directly proportional |
| B. | inversely proportional |
| C. | curvilinearly related |
| D. | none of the mentioned |
| Answer» A. directly proportional | |
| Explanation: the stress is directly proportional to the load and here the load is in terms of bending. so the stress is directly proportional to bending. | |
| 16. |
Which stress comes when there is an eccentric load applied? |
| A. | shear stress |
| B. | bending stress |
| C. | tensile stress |
| D. | thermal stress |
| Answer» B. bending stress | |
| Explanation: when there is an eccentric load it means that the load is at some distance | |
| 17. |
On bending of a beam, which is the layer which is neither elongated nor shortened? |
| A. | axis of load |
| B. | neutral axis |
| C. | center of gravity |
| D. | none of the mentioned |
| Answer» B. neutral axis | |
| Explanation: when a beam is in bending the layer in the direction of bending will be in compression and the other will be in tension. one side of the neutral axis will be shortened and the other will be elongated. | |
| 18. |
The bending stress is |
| A. | directly proportional to the distance of layer from the neutral layer |
| B. | inversely proportional to the distance of layer from the neutral layer |
| C. | directly proportional to the neutral layer |
| D. | does not depend on the distance of layer from the neutral layer |
| Answer» A. directly proportional to the distance of layer from the neutral layer | |
| Explanation: from the bending equation m/i | |
| 19. |
Consider a 250mmx15mmx10mm steel bar which is free to expand is heated from 15C to 40C. what will be developed? |
| A. | compressive stress |
| B. | tensile stress |
| C. | shear stress |
| D. | no stress |
| Answer» D. no stress | |
| Explanation: if we resist to expand then only stress will develop. here the bar is free to expand so there will be no stress. | |
| 20. |
The safe stress for a hollow steel column which carries an axial load of 2100 kN is 125 MN/m2. if the external diameter of the column is 30cm, what will be the internal diameter? |
| A. | 25 cm |
| B. | 26.19cm |
| C. | 30.14 cm |
| D. | 27.9 cm |
| Answer» B. 26.19cm | |
| Explanation: area of the cross section of column = π/4 (0.302 – d2) m2 | |
| 21. |
Stress intensity factor is the critical value of stress at which crack extension occurs. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: stress intensity specifies the stress intensity at the tip of the crack. | |
| 22. |
Fracture toughness does not depend upon geometry of the part containing crack |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: fracture toughness is directly proportional to a factor y that depends upon geometry of the part having crack. | |
| 23. |
How many modes are there for crack propagation? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» B. 3 | |
| Explanation: opening, sliding and tearing are the 3 modes. | |
| 24. |
A curved beam has neutral axis is curved while loaded and straight when unloaded. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: curved beam’s neutral axis is always curved irrespective of the loading. | |
| 25. |
The bending stress in a straight beam varies linearly with the distance from neural axis like that in a curved beam. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: bending stress in a curved beam varies hyperbolically with the distance from neutral axis. | |
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