McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 151. |
Crucible for melting of metals are made of |
| A. | Cast iron |
| B. | Chromium |
| C. | Graphite |
| D. | Hard metal |
| E. | Tungsten |
| Answer» C. Graphite | |
| 152. |
In anti-ferromagnetic materials the spin moments associated with two sets of atoms are aligned |
| A. | Anti-parallel to each other |
| B. | Parallel to each other |
| C. | Random to each other |
| D. | Anti-parallel but of unequal magnitudes |
| E. | None of the above |
| Answer» A. Anti-parallel to each other | |
| 153. |
Ultimate tensile strength is least in case of mild steel and is of the order of |
| A. | 75 - 90 kg/mm2 |
| B. | 60 - 75 kg/mm2 |
| C. | 90 - 100 kg/mm2 |
| D. | 50 - 60 kg/mm2 |
| E. | 35 - 45 kg/mm2 |
| Answer» E. 35 - 45 kg/mm2 | |
| 154. |
Which of the following is not true for cementite? |
| A. | It has low melting point |
| B. | It is found is steels |
| C. | It is brilliantly white |
| D. | It is hard |
| E. | It is brittle |
| Answer» A. It has low melting point | |
| 155. |
Which of the following furnace is used for steel only? |
| A. | Indirect arc furnace |
| B. | Cupola |
| C. | Low specific heat of quenching oil |
| D. | Open hearth furnace |
| E. | Air furnace |
| Answer» D. Open hearth furnace | |
| 156. |
The correct order of cooling media for decreasing cooling rate is |
| A. | Water, oil, fused alst, air |
| B. | Water, air, fused salt, oil |
| C. | Oil, fused salt, air, water |
| D. | Air, water, oil, fused salt |
| E. | Cast iron |
| Answer» A. Water, oil, fused alst, air | |
| 157. |
Quenching cracks during heat treatment can be minimised |
| A. | by avoiding sharp projections and sudden transitions from thick to thin sections |
| B. | articles should be free from stress before heat treatment |
| C. | heat to minimum stable temperature for hardening |
| D. | Any of the above |
| E. | Low specific heat of quenching oil |
| Answer» D. Any of the above | |
| 158. |
In high frequency heating of steel, the heat is generated primarily due to |
| A. | Stray magnetic fields |
| B. | High voltage |
| C. | High resistance of contact surface |
| D. | High power |
| E. | Eddy currents |
| Answer» E. Eddy currents | |
| 159. |
During burning of grain boundaries |
| A. | regions enriched in carbon are formed in first state of burning |
| B. | non-oxidized cavities and blow holes are formed during second stage |
| C. | iron oxide inclusions are formed in third stage |
| D. | All of the above |
| E. | Low specific heat of quenching oil |
| Answer» D. All of the above | |
| 160. |
For nitriding, the nitrogen is provided by |
| A. | Ionised air |
| B. | Heated air |
| C. | Nitric acid |
| D. | Ammonia |
| E. | Nitrous oxide |
| Answer» D. Ammonia | |
| 161. |
Which of the following is closest to the purest form of iron |
| A. | Mild steel |
| B. | Pig iron |
| C. | Nodular cast iron |
| D. | Grey cast iron |
| E. | Wrought iron |
| Answer» E. Wrought iron | |
| 162. |
Eddy currents |
| A. | Increase with square of frequency |
| B. | Increase with fourth power of frequency |
| C. | Increase with frequency |
| D. | Increase as inverse of frequency |
| E. | Increase with cube of frequency |
| Answer» A. Increase with square of frequency | |
| 163. |
Which of the following is fluxing material for cupola? |
| A. | Limestone |
| B. | Fluorspar |
| C. | Soda Ash |
| D. | Any of the above |
| E. | None of the above |
| Answer» D. Any of the above | |
| 164. |
In which of the following cases creep is an important consideration? |
| A. | Cast iron water pipes |
| B. | Cycle chains |
| C. | Gas turbine blades |
| D. | Steam engine flywheel |
| E. | All of the above |
| Answer» C. Gas turbine blades | |
| 165. |
Percentage of carbon in mild steel is |
| A. | 0.010 to 0.025 |
| B. | 1.0 to 1.25 |
| C. | 0.10 to 0.25 |
| D. | 3.0 to 4.50 |
| E. | 0.8 to 0.85 |
| Answer» C. 0.10 to 0.25 | |
| 166. |
The crystal structure of gamma iron is |
| A. | Cubic |
| B. | BCC |
| C. | FCC |
| D. | HCC |
| E. | Any of the above |
| Answer» C. FCC | |
| 167. |
Constantan is an alloy containing |
| A. | Copper and nickel |
| B. | Lead and zinc |
| C. | Copper and zinc |
| D. | Zinc and nickel |
| E. | Lead and copper |
| Answer» A. Copper and nickel | |
| 168. |
Which of the following constituent will increase the hardness of steel? |
| A. | Martensite |
| B. | Pearlite |
| C. | Austenite |
| D. | Cementite |
| E. | All of the above |
| Answer» A. Martensite | |
| 169. |
The depth of hardness in steel can be increased by the addition of |
| A. | Vanadium |
| B. | Chormium |
| C. | Tungsten |
| D. | Sulphur |
| E. | Nickel |
| Answer» B. Chormium | |
| 170. |
The coordination number of NaCl is |
| A. | 2 |
| B. | 9 |
| C. | 8 |
| D. | 3 |
| E. | 6 |
| Answer» E. 6 | |
| 171. |
Babbit metal is an alloy of |
| A. | Tin, copper and lead |
| B. | Tin, antimony and copper |
| C. | Tin, zinc and copper |
| D. | Tin, antimony and lead |
| E. | Lead, zinc and copper |
| Answer» B. Tin, antimony and copper | |
| 172. |
Hypoeutectoid steel has the structure of |
| A. | Cementite |
| B. | Pearlite |
| C. | Ferrite |
| D. | Ferrite & pearlite |
| E. | None of the above |
| Answer» D. Ferrite & pearlite | |
| 173. |
Which of the following hardening process is generally used for non-ferous materials? |
| A. | Nitriding |
| B. | Age hardening |
| C. | Pack carburizing |
| D. | Cyaniding |
| E. | Flame hardening |
| Answer» B. Age hardening | |
| 174. |
Which metal has the highest melting point? |
| A. | Antimony |
| B. | Low specific heat of quenching oil |
| C. | Gold |
| D. | Chromium |
| E. | Stainless steel |
| Answer» D. Chromium | |
| 175. |
Angularity of the square base pyramid in Vickers hardness tester is |
| A. | 90? |
| B. | 11? |
| C. | 120? |
| D. | 150? |
| E. | 136? |
| Answer» E. 136? | |
| 176. |
Modulus of elasticity for steel is approximately |
| A. | 52 x 106 kg/cm2 |
| B. | 1.2 x 106 kg/cm2 |
| C. | 12 x 106 kg/cm2 |
| D. | 2 x 106 kg/cm2 |
| E. | 78 x 106 kg/cm2 |
| Answer» D. 2 x 106 kg/cm2 | |
| 177. |
Maximum hardness that can be achieved in plain carbon steel is of the order of |
| A. | There is no such limit for hardness |
| B. | 100 - 150 Rockwell 'C' |
| C. | 66 - 67 Rockwell 'C' |
| D. | 50 Rockwell 'C' |
| E. | 80-85 Rockwell 'C' |
| Answer» C. 66 - 67 Rockwell 'C' | |
| 178. |
The principle on which a disappearing filamment type pyrometer works is known as |
| A. | Wien's law |
| B. | Peltier effect |
| C. | Kirchhoff's law |
| D. | Seeback effect |
| E. | Fourier's law |
| Answer» A. Wien's law | |
| 179. |
The percentage of sulphur in steel can be reduced by adding |
| A. | Copper |
| B. | Chormium |
| C. | Magnesium |
| D. | Manganese |
| E. | Zinc |
| Answer» D. Manganese | |
| 180. |
Cold worked components are generally subjected to |
| A. | Shot peenling |
| B. | Normalising |
| C. | Hardening |
| D. | Sherodising |
| E. | Annealing |
| Answer» E. Annealing | |
| 181. |
If the structure of a sample consists of pearlite, cementite and free carbon, the sample may be |
| A. | Cast iron |
| B. | Alloy steel |
| C. | Dead mild steel |
| D. | Eutectoid steel |
| E. | None of the above |
| Answer» A. Cast iron | |
| 182. |
During heat treatment quenching cracks occur due to |
| A. | irregular martensitic transformation within the article |
| B. | oxidising atmosphere within the fumace |
| C. | heating at higher temperatures for longer durations |
| D. | All of the above |
| E. | Low specific heat of quenching oil |
| Answer» A. irregular martensitic transformation within the article | |
| 183. |
If during spark test, a sample gives dull red sparks, it could be |
| A. | Mild steel |
| B. | Medium carbon steel |
| C. | Cast iron |
| D. | Non-ferrous material |
| E. | Wrought iron |
| Answer» C. Cast iron | |
| 184. |
Welding process used in fabrication of car bodies is |
| A. | Brazing |
| B. | Soldering |
| C. | Thermit welding |
| D. | Arc welding |
| E. | Resistance welding |
| Answer» E. Resistance welding | |
| 185. |
Approximate Brinell Hardness number for talc is |
| A. | 20 -- 30 |
| B. | 1 |
| C. | 5 -- 10 |
| D. | 2 |
| E. | 50 -- 80 |
| Answer» A. 20 -- 30 | |
| 186. |
The process for steel making being used at Rourkela steel plant is |
| A. | Open hearth process |
| B. | L-D process |
| C. | Electric process |
| D. | Bessemmer process |
| E. | Duplex process |
| Answer» B. L-D process | |
| 187. |
The hardness obtained by hardening process does not depend upon |
| A. | Carbon content |
| B. | Work size |
| C. | Atmospheric temperature |
| D. | Quenching rate |
| E. | None of the above |
| Answer» C. Atmospheric temperature | |
| 188. |
Austenitic stainless steels contain chromium and nickel in amounts required to assure that even at room temperatures, the steels retain their crystalline structures, which are |
| A. | Face centred cubic |
| B. | Diamond cubic |
| C. | Hexagonal closed-packed |
| D. | Partly amorphous |
| E. | None of the above |
| Answer» A. Face centred cubic | |
| 189. |
The process used for making steel is |
| A. | Bessemer converter |
| B. | Open hearth |
| C. | Electric arc |
| D. | High frequency heating |
| E. | Any of the above |
| Answer» E. Any of the above | |
| 190. |
Formation of thick layer of scale on the surface of steel articles can be minimised by |
| A. | heating in furnaces with reducing neutral or protective atmosphere |
| B. | heating in boxes with used carburising agent or cast iron chips |
| C. | heating in molten salt bath |
| D. | Any of the above |
| E. | Low specific heat of quenching oil |
| Answer» D. Any of the above | |
| 191. |
Carbon percentage in steel for carburizing is usually |
| A. | 0.15 percent |
| B. | 0.6 percent |
| C. | 1 percent |
| D. | 0.8 percent |
| E. | 1.5 percent |
| Answer» A. 0.15 percent | |
| 192. |
The operation that usually follwos hardening is |
| A. | Tempering |
| B. | Normalising |
| C. | Annealing |
| D. | Carburising |
| E. | Cyaniding |
| Answer» B. Normalising | |
| 193. |
Which of the following gives a fracture crystalline in appearance? |
| A. | Steel |
| B. | Wrought iron |
| C. | Cast iron |
| D. | All of the above |
| E. | None of the above |
| Answer» C. Cast iron | |
| 194. |
On Moh's scale, materials with hardness number less than 4 are |
| A. | Topaz, Corundum, Diamond |
| B. | Hardened and tempered |
| C. | Felspar, corundum, Diamond |
| D. | Fluorite, Felsper, Talc |
| E. | Talc, gypsum, calcite |
| Answer» E. Talc, gypsum, calcite | |
| 195. |
Highest melting point is for |
| A. | Cast iron |
| B. | Wrought iron |
| C. | Low carbon steel |
| D. | Mild steel |
| E. | High carbon steel |
| Answer» B. Wrought iron | |
| 196. |
Petrol engine carburetors are manufactured by |
| A. | Die casting |
| B. | Lost wax casting |
| C. | Sand casting |
| D. | Centrifugal casting |
| E. | Shell casting |
| Answer» A. Die casting | |
| 197. |
Which metal has the highest melting point? |
| A. | Aluminium |
| B. | Copper |
| C. | Iron |
| D. | Magnesium |
| E. | Silver |
| Answer» C. Iron | |
| 198. |
Bronze is an alloy |
| A. | Copper, lead and tin |
| B. | Copper, zinc and tin |
| C. | Copper, zinc and tin |
| D. | Zinc, nickel and tin |
| E. | Nickel, aluminium and copper |
| Answer» C. Copper, zinc and tin | |
| 199. |
Which of the following material does not have hexagonal close packed structure? |
| A. | Alpha iron |
| B. | Zinc |
| C. | Magnesium |
| D. | Cadmium |
| E. | Titanium |
| Answer» A. Alpha iron | |
| 200. |
The minimum carbon percentage required in steel so that it may respond to hardening by heat treatment is |
| A. | 0.02 percent |
| B. | 0.08 percent |
| C. | 0.2 percent |
| D. | 0.8 percent |
| E. | Low specific heat of quenching oil |
| Answer» C. 0.2 percent | |
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