181. The least preferred technique in the disposal of Municipal Solid Waste is :
1. Incineration
2. Composting
3. Land filling
4. Briquetting
Option “D” is correct Briquetting technology is used to densify the loose combustible materials into solid composites of different shapes and sizes with the presence of pressure and binding agents.
182. Which gas is known as ‘noble gas”?
1. Hydrogen
2. Oxygen
3. Helium
4. Carbon dioxide
Option “C” is correct The noble gases make a group of chemical elements with similar properties under standard conditions, they are all odourless, colourless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and the radioactive Radon (Rn).
183. Which one of the following is coated on the photographic plate?
Option “B” is correct High resolution photographic plates having a coating of exceedingly fine-grained photosensitive emulsions with sub microscopic crystals of silver bromide in gelatin.
184. Methane gas producing field is-
1. Wheatfield
2. Paddy field
3. Cotton field
4. Groundnut field
Option “B” is correct Paddy fields are a major source of atmospheric methane .
185. A polymer used for making nonstick surface coating for utensils is-
Option “B” is correct Polytetrafluoroethylene (PTFE) is usually known as Teflon. This is especially used for making a non-stick surface coating for utensils.
Option “A” is correct Nitrous Oxide (N2O) is also known as laughing gas. It is a colourless gas with a sweet odour and taste. It is also used as the anesthetic gas.
Option “A” is correct Nila thotha is a compound of Copper and sulphate. Its chemical formula is CuSO4.5H2O.
188. Which one of the following takes place during a nuclear fusion?
1. a heavy nucleus bombarded by neutrons breaks up
2. a heavy nucleus breaks up spontaneously
3. two light nuclei combine to form a heavy nucleus
4. a light nucleus breaks up spontaneously
Option “C” is correct Nuclear fusion is a nuclear reaction in which two or more atomic nuclei (e.g. D+T) collide at a very high energy and fuse together.
189. The salt concentration (measured as salinity in parts per thousand), is less than ______ % in inland waters.
1. 5
2. 20
3. 50
4. 75
Option “A” is correct The salt concentration (measured as salinity in parts per thousand), is less than 5 % in inland waters.
190. ___________ is obtained by evaporation of sea.
1. Sugar
2. Iron
3. Salt
4. Steel
Option “C” is correct Salt is obtained from seawater by process of evaporation.
