21. The most serious manufacturing defect from fracture toughness point of view is____________________?
A. Surface roughness
C. Spherical inclusion
22. 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
23. Fatigue limit improvement by over stressing the metal by successively increasing the load is called coaxing. In fatigue failure, the material fails ?
A. Below the yield point
B. Above the yield point
C. Below the elastic limit
D. At the elastic limit
24. Which of the following is not the function of a volute casing provided in a centrifugal pump ?
A. To reduce the head loss in discharge
B. To increase the pump efficiency
C. To collect liquid from the periphery of the impeller and to transmit it to the delivery pipe at
D. To increase the pump discharge rate
25. The capacity of a spring to store energy is called the spring form co-efficient. Stiffness of a spring is measured by the____________________?
A. Ability to absorb shock
B. Capacity to store energy
C. Ratio of the wire & coil diameters
D. Load to produce unit deflection
26. Galvanic corrosion cannot be prevented by___________________?
A. Cathodic protection
B. Anodic protection
C. Usage of largest possible anodic area
D. Any one of these
27. Ceramic compounds as compared to metallic compounds ____________________ ?
A. Crystallise faster
B. Resist greater tensile stress at room temperature
C. Have higher melting temperature
D. Are better conductor of electricity at higher temperature
28. Air-petrol ratio for maximum power generation in spark ignition engine is about_____________________?
A. 6 : 1
B. 12 : 1
C. 18 : 1
D. 24 : 1
29. In an amorphous material, atoms defy any definite atomic structure and exist in random pattern just like in liquid. Which of the following is an amorphous material ?
30. ______________ has the highest melting point out of the following ?