491. Sintered and tungsten carbides can be machined by
A.Brazing
B.Electro-machining process
C.Diamond tools
D.Hot machining

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492. The machining rate in ultrasonic machining is high in case of following material
A.Hard
B.Brittle
C.Ductile
D.Malleable

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493. Spark erosion machining method can be used for the machining of
A.Conducting materials only
B.Non-conducting materials only
C.Semi-conductors only
D.Both conducting and non-conducting materials

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494. For machining to take place by spark erosion
A.The tool must be immersed in the dielectric fluid
B.The work must be immersed in the dielectric fluid
C.Both tool and work must be immersed in the dielectric fluid
D.No dielectric fluid is to be used

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495. In spark erosion machining process, removal of metal takes place during
A.Charging of the capacitor
B.Discharging of the capacitor
C.All times
D.Alternate cycles only

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496. In spark machining, erosion takes place
A.On the job
B.On the tool
C.On both job and tool
D.On the dielectric itself

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497. Ultrasonic machining removes material by
A.Direct vibration of tool with workpiece
B.Using abrasive slurry between tool and work
C.Vibrating air in vicinity of tool and workpiece and making no contact
D.All of the above

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