UGC NTA NET/JRF Exam, Environmental Sciences, March-2023

Total Questions: 100

41. Which of the following are the standard (average) sea level pressure?

(a) 101325 Nm⁻²
(b) 14.69595 psi
(c) 29.92126 inch Hg
(d) 10.33227 m H₂O
(e) 1013.25 kPa
Choose the correct answer from the options given below:

Correct Answer: B. (a), (b), (c) and (d) only
Solution:


42. Choose the correct statements:

(a) VOC, NOx and sunlight are essential for photochemical smog.
(b) Photochemical smog is predominantly formed during the summer season.
(c) NO₂ dissociates by sunlight at 300-400 nm.
(d) Molecular O₂, dissociate by sunlight and provide atomic O for O₃ formation in troposphere.
(e) Tropospheric O₃ concentration is maximum at noon on a given day.
Choose the correct answer from the options given below:

Correct Answer: B. (a), (b), (c) and (e) only
Solution:

43. The elemental analysis in an environmental sample can be performed using:

(a) UU-VIS spectrophotometer
(b) AAS
(c) ICP-OES
(d) XRF
(e) XRD
Choose the correct answer from the options given below:

Correct Answer: D. (a), (b), (c) and (d) only
Solution:

44. Choose the correct statements:

(a) Temperature has a effect in disinfection treatment of water.
(b) pH controls the amount of HOCl and OCI in water.
(c) Cl₂ gas used for disinfection forms HCI as a product in water.
(d) Disinfection action is because of HOСl formed and not due to Cl₂ gas.
(e) Combined chlorine exist in water due to combination of HOCI with NH₃ and organic compounds.
Choose the correct answer from the options given below: 

Correct Answer: C. (a), (b), (c), (d) and (e)
Solution:

45. Choose the correct statement:

(a) UV-C breaks down O₂, molecule in the stratosphere.
(b) A 1% decrease in the overhead O₃ in the stratosphere results in 2% increase in UV-B intensity at the ground level.
(c) UV-A is biologically, the least harmful.
(d) UV-B helps in O₃ dissociation in the stratosphere.
(e) Chapman mechanism deals with both, O₃ formation and destruction, in the stratosphere.
Choose the correct answer from the options given below:

Correct Answer: C. (a), (b), (c), (d) and (e)
Solution:

46. Metals used in wood preservatives are

(a) Cu
(b) As
(c) Se
(d) Cr
(e) Mo
Choose the correct answer from the options given below:

Correct Answer: B. (a), (b) and (d) only
Solution:

Metals such as copper (Cu), arsenic (As), and chromium (Cr) have been historically used in wood preservatives to protect wood from decay, fungi, and insect damage.

The combination of these metals, especially in the form of Chromated Copper Arsenate (CCA), has been a primary wood preservative for many years.

This treatment ensures a longer lifespan for wooden structures. However, concerns about the environmental and health effects of arsenic leaching from CCA-treated wood have led to restrictions in its use, especially for residential purposes. Selenium (Se) and molybdenum (Mo) are not standard components of wood preservatives.

47. The biotic structure of the ecosystem is characterized by the composition of the biological community including:

(a) species numbers
(b) biomass
(c) life-form
(d) life-history
(e) spatial distribution
Choose the correct answer from the options given below: 

Correct Answer: D. (a), (b), (c), (d) and (e)
Solution:

48. The international stable isotope standard Vienna Peedee Belemnite (VPDB) is used for the following stable isotope systems:

(a) ³⁴S/³²S
(b) ²H/¹H
(c) ¹⁸O/¹⁶O
(d) ¹⁶N/¹⁵N
(e) ¹³C/¹²С
Choose the correct answer from the options given below:

Correct Answer: C. (c) and (e) only
Solution:

49. Orthoclace weathers to produce:

(a) silica
(b) dissolved K ion
(c) smectite
(d) kaolinite
(e) dissolved biocarbonate ion
Choose the correct answer from the options given below:

Correct Answer: D. (a), (b), (d) and (e) only
Solution:

50. The variability in height of tropopause is dependent on following factors:

(a) Longitude
(b) Latitude
(c) Temperature
(d) Season
(e) Vegetation
Choose the correct answer from the options given below:

Correct Answer: B. (b), (c) and (d) only
Solution: