State whether the following statements are
true or false :
1. Gold is a ferromagnetic substance.
2. Chemically magnetite is Fe2O3.
3.Artificial magnets are more powerful than natural magnets.
4.Coins are attracted to a bar magnet as they contain nickel.
5.A U-shaped permanent magnet attracts iron less strongly than a bar magnets.
Answers
Answer:
1. False. Not all gold are ferromagnetic substance.
2. True. Iron(II,III) oxide is the chemical compound with formula Fe3O4. It occurs in nature as the mineral magnetite. It is one of a number of iron oxides, the others being iron(II) oxide (FeO), which is rare, and iron(III) oxide (Fe2O3) also known as hematite.
3. True. Artificial magnets are preferred over natural magnets because natural magnets are weak and often irregular in shape, they can readily be magnetised and demagnetised by turning the current on or off in the coil.
4. False. The element Nickel (Ni) is one of the few ferromagnetic metals. Ferromagnetic means they are attracted to magnets and can be magnetized themselves. Most metals aren't magnetic with the exception of iron, nickel, cobalt, gadolinium, neodymium and samarium.
5. False. The reluctance, that is , magnetic resistance in the iron material less compared to other things. So, the iron material can be magnetised faster.
Explanation:
Hope it helps.