1
JEE Main 2020 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Biochemical Oxygen Demand (BOD) is the amount of oxygen required (in ppm):
A
for sustaining life in a water body.
B
by anaerobic bacteria to breakdown inorganic waste present in a water body.
C
for the photochemical breakdown of waste present in 1 m3 volume of a water body.
D
by bacteria to break-down organic waste in a certain volume of a water sample.
2
JEE Main 2020 (Online) 8th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Among the gases (a) – (e), the gases that cause greenhouse effect are :
(a) CO2
(b) H2O
(c) CFCs
(d) O2
(e) O3
A
(a), (b), (c) and (d)
B
(a) and (d)
C
(a), (b), (c) and (e)
D
(a), (c), (d) and (e)
3
JEE Main 2019 (Online) 12th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
The primary pollutant that leads to photochemical smog is :
A
acrolein
B
ozone
C
sulphur dioxide
D
nitrogen oxides
4
JEE Main 2019 (Online) 12th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
The correct set of species responsible for the photochemical smog is :
A
NO, NO2, O3 and hydrocarbons
B
N2, NO2 and hydrocarbons
C
CO2, NO2, SO2 and hydrocarbons
D
N2, O2, O3 and hydrocarbons
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