MCQOPTIONS
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MCQOPTIONS
This section includes 303 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
The inner cone of the flame in welding has the following nature? |
| A. | highest temperature |
| B. | coldest temperature |
| C. | moderate temperature |
| D. | uncertain |
| Answer» B. coldest temperature | |
| 202. |
Amount of time during which the transformer will be used for welding under normal loading condition is known as? |
| A. | hold time |
| B. | off time |
| C. | weld time |
| D. | duty cycle |
| Answer» E. | |
| 203. |
For brazing, soldering and flame hardening which of the following flame is used? |
| A. | neutral flame |
| B. | oxidizing flame |
| C. | carburizing flame |
| D. | both oxidizing flame and carburizing flame |
| Answer» D. both oxidizing flame and carburizing flame | |
| 204. |
In which of the following type of flame, oxygen is deficient in proportion with acetylene? |
| A. | neutral flame |
| B. | oxidizing flame |
| C. | carburizing flame |
| D. | both oxidizing flame and carburizing flame |
| Answer» D. both oxidizing flame and carburizing flame | |
| 205. |
In which of the following type of flame, oxygen is in excess proportion with acetylene? |
| A. | neutral flame |
| B. | oxidizing flame |
| C. | carburizing flame |
| D. | both oxidizing flame and carburizing flame |
| Answer» C. carburizing flame | |
| 206. |
How many types of flames are there in welding? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 207. |
Which of the following is also called “gas welding� |
| A. | oxy fuel gas welding |
| B. | metallic welding |
| C. | arc welding |
| D. | fuel gas welding |
| Answer» B. metallic welding | |
| 208. |
Which of the following gases are used in Tungsten inert gas welding? |
| A. | helium and neon |
| B. | hydrogen and oxygen |
| C. | argon and helium |
| D. | carbon dioxide and hydrogen |
| Answer» D. carbon dioxide and hydrogen | |
| 209. |
The coating material used for the electrode is termed as? |
| A. | flux |
| B. | slag |
| C. | protective layer |
| D. | deoxidiser |
| Answer» B. slag | |
| 210. |
Which of the following materials necessitates preheating in welding? |
| A. | copper |
| B. | aluminium |
| C. | cast iron |
| D. | stainless steel |
| Answer» D. stainless steel | |
| 211. |
The maximum diameter of electrodes being used in submerged arc welding? |
| A. | 30 mm |
| B. | 20 mm |
| C. | 15 mm |
| D. | 10 mm |
| Answer» E. | |
| 212. |
Which of the following welding process in which heat is produced for welding by a chemical reaction? |
| A. | resisting welding |
| B. | thermit welding |
| C. | forge welding |
| D. | gas welding |
| Answer» C. forge welding | |
| 213. |
In resistance welding, between the electrodes, the nature of current and voltage parameters being used? |
| A. | high current, high voltage |
| B. | low current, high voltage |
| C. | low current, low voltage |
| D. | high current, low voltage |
| Answer» E. | |
| 214. |
Due to which of the following reasons, flux is not used in atomic hydrogen welding? |
| A. | the burning hydrogen shields the molten metal |
| B. | two electrodes are coated which gradually release the flux |
| C. | the filler rod is coated with flux |
| D. | one of the two electrodes is coated which releases the flux |
| Answer» B. two electrodes are coated which gradually release the flux | |
| 215. |
For grey cast iron, which of the following welding methods is preferable? |
| A. | mig |
| B. | submerged arc |
| C. | gas flame |
| D. | electric arc |
| Answer» B. submerged arc | |
| 216. |
Which of the following brazing process is good for mass scale joining? |
| A. | furnace |
| B. | induction |
| C. | dip |
| D. | torch |
| Answer» B. induction | |
| 217. |
In which of the following welding processes we use two non-consumable electrodes? |
| A. | mig |
| B. | tig |
| C. | atomic hydrogen |
| D. | submerged arc |
| Answer» D. submerged arc | |
| 218. |
Upon which of the following parameters does the current intensity in arc welding depend? |
| A. | stability of arc |
| B. | electrode diameter |
| C. | gap between the electrode and parent metals |
| D. | thickness of parent metals |
| Answer» C. gap between the electrode and parent metals | |
| 219. |
volts, I = 200 A, and the cross-sectional area of the weld bead is 30 mm2. Estimate the welding speed if the workpiece and electrode are made of (a) aluminum, (b) carbon steel, and (c) titanium. Use an efficiency of 75%. |
| A. | 35 mm/s |
| B. | 34.5 mm/s |
| C. | 36 mm/s |
| D. | 46 mm/s |
| Answer» C. 36 mm/s | |
| 220. |
The starting method for a 3-phase squirrel-cage induction motor which is inferior in view of poor starting torque per ampere of line current drawn is? |
| A. | series-inductor method of starting |
| B. | direct-on-line starting |
| C. | auto-transformer method |
| D. | star-delta method |
| Answer» B. direct-on-line starting | |
| 221. |
If use auto transformer method starting to start an induction motor to replace star-delta method, then the required tapping on the transformer will be |
| A. | 57.73% |
| B. | 86.7% |
| C. | 57% |
| D. | 66.66% |
| Answer» B. 86.7% | |
| 222. |
and the rotor current I2 are zero at |
| A. | ns |
| B. | 2ns |
| C. | zero |
| D. | slip of 50% |
| Answer» B. 2ns | |
| 223. |
A three phase induction motor is sometimes calles a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is equal to stator frequency? |
| A. | it will not operate |
| B. | it will operate as induction motor only |
| C. | it will operate as induction generator |
| D. | it will operate in braking mode |
| Answer» B. it will operate as induction motor only | |
| 224. |
Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have better full-load power factor? |
| A. | a |
| B. | b |
| C. | both a and b |
| D. | neither a nor b |
| Answer» C. both a and b | |
| 225. |
Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have poorer power factor? |
| A. | a |
| B. | b |
| C. | both a and b |
| D. | neither a nor b |
| Answer» B. b | |
| 226. |
Two three phase induction motors A and B are identical in all respects except that motor A has a larger air-gap than motor B. Which motor will have more no load current? |
| A. | a |
| B. | b |
| C. | both a and b |
| D. | neither a nor b |
| Answer» B. b | |
| 227. |
The direction of rmf when a three phase supply is given to stator of three phase induction motor is? |
| A. | zero |
| B. | ns |
| C. | 2ns |
| D. | -ns |
| Answer» C. 2ns | |
| 228. |
The direction of rmf when a single phase supply is given to stator of three phase induction motor is? |
| A. | zero |
| B. | ns |
| C. | 2ns |
| D. | -ns |
| Answer» B. ns | |
| 229. |
Defect which occurs due to the solidification of casting is known as? |
| A. | swell |
| B. | misrun |
| C. | metal penetration |
| D. | shrinkage cavity |
| Answer» E. | |
| 230. |
Which defect is caused due to the conversion of moisture to steam because of the heat of molten metal? |
| A. | blow holes |
| B. | open blows |
| C. | air inclusions |
| D. | cold shut |
| Answer» B. open blows | |
| 231. |
During melting process flux is added to react with impurities to form? |
| A. | cavity |
| B. | slag |
| C. | cold shut |
| D. | blow holes |
| Answer» C. cold shut | |
| 232. |
Defects caused by the chilling of the casting are known as? |
| A. | hot spots |
| B. | hot tears |
| C. | shrinkage cavity |
| D. | swell |
| Answer» B. hot tears | |
| 233. |
The lower fluidity of molten material causes |
| A. | misrun |
| B. | cold shut |
| C. | misrun & cold shut |
| D. | fusion |
| Answer» D. fusion | |
| 234. |
When the molten metal leaks out of mould which defect occurs? |
| A. | run out |
| B. | misrun |
| C. | fusion |
| D. | drop |
| Answer» B. misrun | |
| 235. |
Cuts, washes, swell, drop etc. are the examples of which of the following casting defects? |
| A. | gas defect |
| B. | pouring material defect |
| C. | moulding material defect |
| D. | metallurgical defect |
| Answer» D. metallurgical defect | |
| 236. |
Which of the following defect is not a gas defect? |
| A. | blow holes |
| B. | air inclusions |
| C. | run out |
| D. | pin hole porosity |
| Answer» D. pin hole porosity | |
| 237. |
Which gas defect is caused by hydrogen in molten metal? |
| A. | blow holes |
| B. | air inclusions |
| C. | open blows |
| D. | pin hole porosity |
| Answer» E. | |
| 238. |
Moisture from the mould can be removed by using of dryer or heater in Co2 moulding. |
| A. | true |
| B. | false |
| Answer» C. | |
| 239. |
Co2 moulding is a kind of sand moulding, but it is not economical than the green sand moulding. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 240. |
Co2 moulding process is an ideal process, where speed and flexibility is the prime requirement. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 241. |
Which of the following additives are added to the sand in Co2 moulding for the improvement in collapsibility of the sand? |
| A. | copper oxide |
| B. | wood flour |
| C. | aluminium oxide |
| D. | oil |
| Answer» D. oil | |
| 242. |
It is very safe to use Co2 in Co2 moulding, so it eliminates the use of any shielding apparatus. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 243. |
How much time (in a minute) is usually required for the passing of Co2 through the mould? |
| A. | one |
| B. | two |
| C. | five |
| D. | seven |
| Answer» B. two | |
| 244. |
Continuous passing of Co2 through the mould can decrease the strength of mould and results in a weak mould. |
| A. | true |
| B. | false |
| Answer» C. | |
| 245. |
How much percentage of sodium silicate (Na2SiO3) is added to the sand mixture in Co2 moulding? |
| A. | 0 to 2 % |
| B. | 2 to 6 % |
| C. | 6 to 10 % d) 10 to 14 % |
| Answer» C. 6 to 10 % d) 10 to 14 % | |
| 246. |
Sometimes over-gassing can cause the sticking of pattern to the mould in Co2 moulding. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 247. |
Which of the following moulds or moulding is also known as sodium silicate process. |
| A. | shell moulding |
| B. | permanent moulding |
| C. | slush moulding |
| D. | co2 moulding |
| Answer» E. | |
| 248. |
In centrifugal casting, a movable pouring basin is employed for the pouring of molten metal. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 249. |
In centrifugal casting, the casting yield is approximately equaled to 100%. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 250. |
The speed of rotation is almost double in semi centrifugal casting as compared to the true centrifugal casting. |
| A. | true |
| B. | false |
| Answer» C. | |