DIRECTION for Q. 40 : This question contain STATEMENT-1 (Assertion) and STATEMENT-2 (Reason) and has 4 choices(a), (b), (c) and (d) out of which ONLY ONE is correct.

Statement 1 :CO₂ causes green house effect.
Statement 2 : Other gases do not show such effect.

Statement- 1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement -1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement - 1 is True, Statement- 2 is False
Both the Statements are False.

Solution

Green house effect is due to the occurrence of high carbon dioxide content, high vapour content and glass walls.Gases like CO₂ are called green house gases because they are transparent to solar radiations (wavelength 0.15- 4.00 µm) but are strong absorbers of long wave or infrared radiations emitted by the surface of the earth.

Which is anon-degradable pollutant ?

Smoke
Polythene
Copper scraps
Iron scraps

Two lakes, A and B are identical in all aspects except that lake A has higher temperature. Which of the following is true ?

A has higher rate of Oxygen dissolution
B has higher rate of Oxygen dissolution
Oxygen dissolution of both is the same
Both have same BOD

The use of DDT is banned now a days because it is

Very costly
Note available
Inflammable
Not degraded easily

DDT causes egg shell thinning in birds because it inhibits

calmodulin
calcium ATPase
magnesium ATPase
carbonic anhydrase

Solution

DDT causes egg shell thinning in birds because it inhibits calcium ATPase.

A lake affected by high levels of artificial eutrophication will have

high nutrient levels, large phytoplankton populations, and low oxygen levels at depth.
high levels of nutrients, low phytoplankton levels, highoxygen levels in surface waters.
low nutrient levels, large phytoplankton populations, and low oxygen levels at depth.
low nutrient levels, low phytoplankton populations, and high oxygen levels at depth

The most common indicator organisms that represents polluted water is :

E. coli
P.typhi
Vibrio
Entamoeba

Solution

E. coli resides in the human large intestine. If they are present in water supply, it can be guess that water supply is contaminated.

Why is the concentration of ozone less over the north and south poles ?

CFCs accumulate only in area where the air is cold
CFC use is highest in these areas
CFCs stick to frozen water vapour and are able to act catalysts
UV rays are stronger in the atmosphere

Which gas of the atmospheric holds up ultraviolet rays ?

O₂
O₃
N₂
CH₄

Ozone layer is formed in which zone of atmosphere

Mesosphere
Stratosphere
Troposphere
Ionosphere

UnAttempted

0

Attempted

0

Correct

0

Wrong

0

Complete