The hardness of a grinding wheel is determined by the
Answer: B
Because each abrasive grain usually removes only a very small amount of material at a time, high rates of material removal can be achieved only if a large number of these grains act together. This is done by using bonded abrasives, typically in the form of a grinding wheel. The abrasive grains are held together by a bonding material which acts as supporting posts or brace between the grains and also increases the hardness of the grinding wheel.