A body of density d1 is counterpoised by M g of weights of density d2 in air of density d. Then the true mass of the body is
Let M_0 mass of body in vacuum. Apparent weight of the body in air = Apparent weight of standard weights in air ⇒Actual weight – upthrust due to displaced air = Actual weight – upthrust due to displaced air ⇒M0g−(M0d1)dg==Mg−(Md2)dg⇒M0=M[1−dd2][1−dd1]