A dental assistant qualified to perform coronal polishing is preparing for the next patient, a 50-year-old smoker who has had a moderate amount of direct composite resin and indirect porcelain posterior restorations placed. Following the patient's adult prophylaxis by the
hygienist, the dental assistant is asked to do selective polishing. What instruments and materials will be required?

answer; i believe the correct answer to the above question is ( friction)

i think that it is c, d, and e, hope this

answer: zinc is the substance which has a volume of 1.38 .

density is defined as the mass of an object per unit volume.

it can be calculated by dividing mass of a substance by its volume i.e.

si unit of density is kg per cubic meter and cgs unit of the same is gram per cubic centimeter.

now from the given data volume can be calculated by the formula .

hence, the volume of aluminium will be = which comes out to be 1.703 .

similarly, volume of zinc, chromium, and nickel will be 1.378 , 0.869 , and 0.356 respectively.