151. Who discovered positrons?
Answer: Carl David Anderson
152. What is
the unit for measuring the pitch or frequency of sound ?
Answer: Decible
153. Who
measured the charge of an electron at first?
Answer: Robert
Andrews Millikan
154. The metal
used in storage batteries —
Answer: Lead
155. The
fastest acting enzyme in the biological kingdom is–
Answer: carbonic
anhydrase
156. Water has
maximum density at —
Answer: –4°C
157.
Lightening cause rainfall because–
Answer: It activate H2O molecule
158.Which one
of the following is also called Stranger Gas?
Answer: Xenon
159. The
chemial name of Uria is —
Answer: Carbamide
160.
Nitrification means–
Answer: Convert
the atmospheric nitrogen to effective nitrogen compound.
161. Permanent
hardness of water can be removed by adding —
Answer: Washing
Soda
162.The
alcohol used in power alcohol is
Answer: ethyl
alcohol
163. Cell
membrane is–
Answer: semipermeable
164.The
chemical used as a fixer in photography is
Answer: sodium
thiosulphate
165. Which of
the following substance is a bad conductor of electricity but a good conductor
of heat?
Answer: Mica
166.
Polythene is industrially prepared by the polymerisation of–
Answer: ethylene
167.The shell
of the egg is made of –
Calcium
Carbonate.
168.Talc is
basic –
magnesium
silicate mineral
169.The
highest and simplest element is hydrojen while the lightest metal is-
Lithium
170. Temporary
hardness of water is due to the bicarbonates of calcium and magnesium. It can
be removed by –
boiling or
adding lime
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