3. In the zone melting approach, which of the following principles was used? a) Impurities concentrate in the liquid phase than in gaseous phase b) Impurities concentrate in the solid than in liquid phase c) Impurities concentrate in the gaseous phase than in the solid phase d) Impurities concentrate in the liquid phase than in the solid phase
Answer: d Explanation: The zone melting approach is based on the idea that impurities tend to concentrate in liquid rather than solid phases. As a result, the moving molten zone sweeps’ impurities out of the crystal. Purification and crystal formation of high melting metals like tungsten have been accomplished using this technology.
