WEBSCTE-2021 (SEM - 6)

All short questions


  • Fill in the blanks :

i) The appropriate percentage of water in sewage is  99.9% .

ii) Activated carbon is used in water treatment for removing  organic chemicals .

iii) The most significant gaseous air pollutant is  SO2 .

iv) Electrostatic precipitators remove  fine particles (like dust and smoke) .

v) The most significant primary gaseous pollutant, found in vehicular emission is  CO .

vi) The lowest layer of atmosphere is called  troposphere .

vii) TSS stands for  total suspended solid .

viii) WHO stands for  world health organisation .

ix) CH4 is known as  natural/green house/methen  gas.

x) Hard water is  less  suitable for boiling.

xi)  sewage and waste water treatment/industrial  waste is a main source of water pollution.

xii) Noise is expressed in  decible  unit.


  • Choose the correct answer from the given alternatives :

i) Which one of the following practices causes reduction in per capita water consumption? –

a) Good quality water, b) Hotter climate, c) Modern living, d) Metering system.

ii) Which source of water, among the following, is not a sub-surface source? –

a) Spring, b) Well, c) Storage reservoir, d) Infiltration gallery.

iii) The valve which allows the flow only in one direction, is a – a) Reflux valve, b) Sluice valve, c) Gate valve, d) None of these.

iv) “Safe Water” is one which does not contain – a) Pathogenic bacteria, b) Turbidity, c) Any taste, d) Any colour.

v) A water having pH equal to 7 is – a) acidic, b) alkaline, c) neutral, d) none of them.

vi) The liquid wastes originating from residential and industrial buildings are collectively called – a) domestic sewage, b) combined sewage, c) sanitary sewage, d) none of them.

vii) World environmental day is – a) 5th June, b) 5th April, c) 5th October, d) 5th December.

viii) The devices which are installed for drawing water from different water sources are called – (a) filters, (b) outlets, (c) intakes, (d) inlets.

ix) When fluoride concentration in eater exceeds1.5 mg/l or so, the disease that may be caused, is – (a) Methaemoglobinemia, (b) Fluorosis, (c) Dental caries in children, (d) Poliomyelitis

x) The secondary treatment of sewage is caused by – (a) bacteria, (b) algae, (c) coagulants, (d) none of them

xi) The polluting gas, which is primarily responsible for causing the green house effect and global warming – (a) sulphur dioxide, (b) hydrogen sulphide, (c) carbon dioxide, (d) none of them.

xii) Standard BOD of water is taken for – (a) 2 days, (b) 3 days, (c) 5 days, (d) 10 days.