1201. Materials used for making permanent magnets containing iron and nickel are made by __________ technique.
A. Powder metallurgy
B. Casting
C. Forging
D. None of these
✅ The correct answer is option C.
1204. Chlorine acts as a bleaching agent only in the presence of
A. Dry air
B. Pure oxygen
C. Moisture
D. Sunlight
✅ The correct answer is option C.
1207. Window panes of aeroplanes are normally made of
A. Perspex (PMMA)
B. Teflon (PTFE)
C. Bakelite (phenol formaldehyde)
D. Polystyrene
✅ The correct answer is option A.
1171. Coke is added in the blast furnace to
A. Reduce & melt the iron ore
B. Increase the fluidity of slag
C. Remove sulphur & phosphorus from molten metal
D. None of these
✅ The correct answer is option A.
1174. Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air.
A. Wet bulb
B. Dry bulb
C. Saturation
D. Dew point
✅ The correct answer is option A.
1177. Main constituent of bone ash is
A. Ammonium phosphate
B. Calcium phosphate
C. Animal charcoal
D. Ammonium sulphate
✅ The correct answer is option B.
1180. Even minute presence of impurities in copper impairs its electrical conductivity seriously. Electrolytic refinning of blister copper is resorted to, when
A. Cheap electricity is available
B. The precious metal content of copper is high
C. There is a demand for ultrapure (99.99%) electrolytic copper
D. All of the above
✅ The correct answer is option D.
1183. Which of the following is not used as a fuel in rocket propellaht ?
A. Liquid hydrogen
B. Liquid oxygen
C. Liquid hydrazine
D. Kerosene oil
✅ The correct answer is option B.
1186. The basic function of the drum in a boiler is to
A. Act as a storage for feed water
B. Act as a storage for steam
C. Separate steam from water
D. Remove settling impurities from steam
✅ The correct answer is option C.
1188. Which of the following is not a characteristic observed in material failure by fatigue fracture ?
A. Plastic deformation of material does not occur
B. Initiation of crack from below the surface does not occur
C. Initation of crack occurs on the surface of the machine part
D. Presence of both rough & smooth zone with conchoidal markings in smooth zone of the surface
✅ The correct answer is option B.