Science Class 7th

221. In screening process of water treatment plant natural contaminates such as plant, woods etc. are removed.

A) Small

B) Middle

C) Large

D) None of these

222.In coagulation and flocculation process of water treatment plant the removal of_______ particles from water take place.

A) Micro

B) Small

C) Suspended

D) None of these

223. Floc settles to the bottom of the tank containing water due to its weight, this process is called

A) Condensation

B) Boiling

C) Sedimentation

D) None of these

224. Water is used for cleaning, washing, drinking, this is the use of water for purpose.

A) Industrial

B) Agricultural

C) Domestic

D) None of these

225. Water is used as coolant, ingredient, reagent etc, this is the use of water for purpose.

A) Domestic

B) Agricultural

C) Industrial

D) Transportation

226. Water is used for farming, gardening etc. This is the use of water for purpose.

A) Communities

B) Recreational

C) Agricultural

D) None of these

227. Harmful bacteria are removed from drinking water by passing :

A) Oxygen gas

B) Nitrogen gas

C) Chlorine gas

D) Carbon dioxide gas

228. Suspended particle from the drinking water are removed by :

A) Table salt

B) Chlorine

C) Charcoal

D) Potash alum

229. Distillation is a technique of :

A) Separation

B) Preparation

C) Filtration

D) Disinfection

230. has mass and occupy space.

A) Water

B) Wood

C) Matter

D) Air

231. are the basic building blocks of matter.

A) Molecule

B) Atoms

C) Ions

D) Chemicals

232. The idea that all matter is made up of atoms was proposed by

A) Rutherford

B) Democritus

C) John Walton

D) None of the above

233. The word atom is derived from the greek word

A) Atomic

B) Atomics

C) Atomos

D) None of these

234. Atoms are composed of types of articles.

A) Four

B) Three

C) Two

D) None of these

235. Electron, protons are basic particles of atom.

A) Protonious

B) Electolysis

C) Neutron

D) None of these

236. Most of the atomic mass is comprised of

A) Proton, electron

B) Electron ,neutron

C) Neutron , proton

D) None of these

237. ______ reside in the nucleus.

A) Electron, proton

B) Neutron , proton

C) Neutron, electron

D) None of these

238. Protons have charge

A) Positive

B) Negative

C) Neutral

D) None of these

239. Neutrons have charge

A) Positive

B) Negative

C) No

D) None of these

240. Electrons have charge.

A) Negative

B) Positive

C) No

D) None of these