Potassium carbonate when heated to high temperature.

''A black dot on as a porcelain cup apppears dark. But when heated to a high temperature it becomes brighter than the rest of the cup.'' Why ?

Carborundum is obtained when silica is heated at high temperature with

Carborundum is obtained when silica is heated at high temperature with

Carborundum is obtained when silica is heated at high temperature with

Carborundum is obtained when silica is heated at high temperature with

If a magnet is heated to a high temperature, it