In upper layer of atmosphere ozone is formed
1). the action of ultraviolet rays on oxygen
2). the combination of oxygen molecules
3). subjecting oxygen to high pressure
4). the action of nitrogen on oxygen in atmosphere
The iron ore which contains 72% of iron is :
1). Magnetite
2). Limonite
3). Haematite
4). Siderite
Raw materials used for the manufacture of glass are
1). sand soda limestone
2). sand charcoal soda
3). limestone charcoal sulphur
4). sand sulphur soda
Which among the following metals provides atmospheric oxide?
1). Sodium
2). Silver
3). Aluminium
4). Calcium
Diamond is harder than graphite because of
1). difference in layers of atoms
2). tetrahedral structure of diamond
3). difference of crystalline structures
4). None of these