9. The most abundant natural Iron oxides are
a) Magnetite and Pyrite
b) Magnetite and Bauxite
c) Hematite and Pyrite
d) Hematite and Magnetite
e) Hematite and Bauxite
10.The most abundant elements in sea water are
a) Sodium and Potassium
b) Sodium and Calcium
c) Sodium and Chlorine
d) Chlorine and Iodine
e) Magnesium and Sulphur
11. An electric current can produce
a) Chemical effect
b) Magnetic effect
c) Heating effect
d) All of these three
e) None of these
12. The unit of home electricity energy consumption is:
a) Watt hour
b) Kilowatt hour
c) Joule hour
d) Kilojoule hour
e) None of these