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Class 12 Biology MCQs Chapter - 16

Class 12 Biology MCQs Chapter – 16

1. Which is the major source of harmful radiations in the house ?

(A) Tube light

(B) Colour TV

(C) Oven

(D) Heater

Answer-( A )


2. Which one is not produced as exhaust of vehicle ?

(A) SO2

(B) CO2

(C) CO

(D) Flyash

Answer-( D )


3. SO2 pollution afects :

(A) Mitochondria

(B) Chloroplast

(C) Golgibodies

(D) ER

Answer-( B )


4. Climate of world is threatened by :

(A) increasing amount of CO2

(B)increasing amount of O2

(C)increasing amount of O3

(D)increasing amount of N2

Answer-( A )


5. Ozone day is celebrated on :

(A) 6 September

(B ) 21 April

(C) 25 December

(D) January 30

Answer-( A )


6. Which is the effect (s) of deforestation

(A) Enhanced CO2 concentration

(B) Desertification

(C) Global warming

(D)All of above

Answer-( D )


7. The cause of Minimata disease is due to poisoing of:

(A) Methyl Mercury

(B) Methyl cyanide

(C) Lead

(D) Copper

Answer-( A )


8. At present the concentration of atmospheric co2 is:

(A) 100 ppm

(B) 240 ppm

(C) 380 ppm

(D) 520 ppm

Answer-( C )


9. Which is related to ‘Polyblend’ ?

(4) Ahmad Khan

(B) Ramesh Chandra Dagar

(C) Ramdev Mishra

(D) Swaminathan

Answer-( A )


10. Photochemical smog consists of

(A) SO2 PAN and smoke

(B) Ozone, PAN and NO2

(C) Ozone, SO2 and Hydrocarbon

(D)SO² CO2 and Hydrocarbon

Answer-( B )


11. Snow blindness in human being is caused by

(A) Absorption of UV B radiation

(B) Absorption of infra radiation

(C) Absorption of cosmic radiation

(D) Erosion of cornea by snow

Answer-( A )


12. The thickness of Ozone in a column of air from the ground to the top of atmosphere is measured in terms of

(A) Dobson unit

(B ) Arab unit

(C) Pascal unit

(D ) None of these

Answer-( A )


13. Which of the following is green house gas?

(A) Methane

(B) CO2

(C) Chloro fluoro carbon

(D ) All of these

Answer-( D )


14. Major source of methane is :

(A) Sugarcane plantation

(B) Rice fields

(C) Fruit orchards

(D) Wheat fields

Answer-( B )


15. Rain is called acid rain when its pH is below :

(A) 7

(B) 6.5

(C) 6

(D) 5.6

Answer-( D )


16. Ozone hole is caused by :

(A) Acetylene

(B) Ethylene

(C) Chlorofluorocarbons

(D) Methane

Answer-( C )


17. Green-house effect is due to :

(A) Higher CO2 concentration

(B) Absorption in infra-red gases and dust particles

(C) Both A and B

(D) Rarefaction of atmosphere

Answer-( C )


18. Indicator of SO2 pollution is :

(A) Algae

(B) Lichen

(C) Fungi

(D) All of these

Answer-( B )


19. Factors of acid rain are

(A) CO and CO2

(B) NO2 and SO2

(C) CO2 and NO2

(D) N2 and NO2

Answer-( B )


20. Generally threshold of sound intensity for human is

(A) 20-30 decibel

(B ) 80-90 decibel

(C) 120-130 decibel

(D) 140-150 decibel

Answer-( A )


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