6. Out of the following, the best material capable of withstanding shock & vibration without the danger of cracking is
A. Malleable iron
B. Grey cast iron
C. Chilled cast iron
D. White cast iron
✅ The correct answer is option A.
9. Machinability of hard alloys & tool steels is improved by
A. Spherodising
B. Annealing
C. Tempering
D. Normalising
✅ The correct answer is option B.
11. Turning/machining of __________ usually does not require any cutting fluid.
A. Cast iron
B. Stainless steel
C. Mild steel
D. Copper
✅ The correct answer is option A.
13. Which of the following does not come under the category of electrochemical corrosion?
A. Corrosion in organic liquids
B. Atmospheric corrosion in moist gas or air
C. Soil corrosion as in the case of underground pipes
D. Corrosion in sea water and molten metals
✅ The correct answer is option A.
15. Air-petrol ratio in an automotive petrol engine is around
A. 14 : 1
B. 22 : 1
C. 25 : 1
D. 4 : 1
✅ The correct answer is option A.
17. Heat treatment of steel is done mainly to change its
A. Mechanical properties
B. Physical properties
C. Chemical composition
D. All of the above
✅ The correct answer is option A.
19. Which is the only metal that exists in liquid state at room temperature?
A. Sodium
B. Mercury
C. Lithium
D. Strontium
✅ The correct answer is option B.
21. Which of the following varies as the square root of oil pressure during atomisation of fuel oil through a pressure jet burner?
A. Output & fineness
B. Velocity
C. Both A & B
D. None of these
✅ The correct answer is option C.
23. More than 1000 tons refrigeration capacity plants are usually of __________ type.
A. Vapour compression
B. Vapour absorption
C. Air refrigeration
D. None of these
✅ The correct answer is option B.
25. The activity co-efficient of the solute in a dilute solution
A. Decreases with the increase of concentration of the solute
B. Increases with the increase of concentration of the solute
C. Remains constant
D. Is unity at infinite dilution
✅ The correct answer is option C.