simple heating

flame heating

induction heating

any one of these

It requires less power than machining metal at room temperature.

the rate of tool wear is lower

it is used for machining high strength and high temperature resistant materials

all of the above

using abrasive slurry between the tool and work

direct contact of tool with the work

maintaining an electrolyte between the work and tool in a very small gap between the two

erosion caused by rapidly recurring spark discharges between the tool and work

electro-chemical machining

electro-discharge machining

ultra-sonic machining

none of these

aluminum oxide

boron carbide

silicon carbide

any one of these