(c) Diamond
     (d) Iron oxide
Ans: (a)
185. The ratio of pure gold in 18 carat gold is:
     (a) 60%
     (b) 75%
     (c) 80%
     (d) 100%
Ans: (b)
186. Actinides are the elements with atomic numbers from: [IFS 1989]
     (a) 36 to 43
     (b) 89 to 103
     (c) 97 to 114
     (d) 101 to 115
Ans: (b)
187. Find the odd one:
     (a) Marble
     (b) Chalk
     (c) Limestone
     (d) Slaked lime
Ans: (d)
188. A super conductor is characterised by:
     (a) zero permeability
     (b) low permeability
     (c) high permeability
     (d) infinite permeability
Ans: (a)
189. Which of the .following elements is obtained from seaweeds?
     (a) Argon
     (b) Sulphur
     (c) Vanadium
     (d) Iodine
Ans: (d)
190. In fireworks, the green flame is produced because of: [CBI 1994]
     (a) mercury
     (b) sodium
     (c) potassium
     (d) barium
Ans: (d)
191. According to Dalton"s atomic theory, the smallest particle which can exist independently is: [UDC 1995]
     (a) an atom
     (b) a molecule
     (c) a cation
     (d) an anion