56.The high-temperature superconductors are :

57.The symbols used to denote different elements are generally the first or the first two letters of the name by which the particular element is commonly known. Which of the following elements do not fall in this category ? 1. Osmium 2. Tungsten3. Silver 4. Antimony

58.The metallic constituents of hard water are :

59.When a cell neither shrinks nor swells when kept in a fluid, then the fluid in the cell in relation to ambient fluid is called :

60.Carbon, diamond and graphite are together called :