NEET Biology Environmental Issues Important Questions Set 02

These Class 12 NEET Biology important questions on Environmental Issues give 23 questions with step-by-step answers, arranged as very short, short and long answer types, taken from a model test paper. They help NEET aspirants revise the definitions, structures, differences and key terms of the chapter.

Very Short Answer Type Questions

Question 1. Which type of UV-radiations can be lethal to organisms?
Answer: UV-B, UV-A

Question 2. Name any three gases contributing to greenhouse effect.
Answer: CO₂, CH₄, N₂O

Question 3. Why are owners of motor vehicles equipped with catalytic converters adviced to use unleaded petrol?
Answer: Because the lead in petrol inactivates the catalyst.

Question 4. Which act included noise as an air pollutant?
Answer: Air (Prevention and Control of Pollution Act) which came into force in 1981 but was amended in 1987 to include noise as an air pollutant.

Question 5. Integrated waste water management project in Arcata is being managed by _______.
Answer: FOAM.

Question 6. What is polyblend?
Answer: Polyblend is a fine powder of recycled modified plastic which was developed by Ahmed Khan's company to lay roads along with bitumen.

Question 7. What is the forest cover in India?
Answer: 19.4%

Question 8. Name the green house gases.
Answer: CO₂, CH₄, CFC and N₂O

Short Answer Type Questions

Question 9. How is nuclear waste stored?
Answer: Nuclear waste is stored in suitably shielded containers buried within rocks about 500 m deep below the earth surface.

Question 10. Define El-Nino effect.
Answer: Increase in the level of greenhouse gases has led to the increase in temperature of Earth by 0.6°C. This has led to deleterious changes in the environment resulting in odd climatic changes (El-Nino effect).

Question 11. What is snow blindness?
Answer: Inflammation of cornea caused by high doses of UV-B radiation is called snow blindness.

Question 12. Explain Jhum cultivation.
Answer: Farmers cut down the trees of the forest and burn the plant remains. The ash is used as fertilizer and the land is then used for farming or cattle grazing. After cultivation the area is left for several years to allow its recovery. The farmers then move on to other areas and repeat this process. This is also called as slash and burn agriculture.

Question 13. Write down the composition of waste water.

Answer:

The composition of waste water: 99.9 % – Water

Question 14. What gases cause stratospheric ozone depletion? What is the result of this depletion?
Answer: Chloroflourocarbons result is the ozone depletion. It has resulted in the formation of a large area of thinned ozone layer commonly called as ozone hole. UV-radiation of wavelength shorter than UV-B are almost completely absorbed by earth atmosphere given that the ozone layer is intact.

Question 15. Name and define these environment-related terms.
(i) DDT accumulated in a three-step food chain will be maximum in secondary consumer.
(ii) Pertaining to cause algal bloom.
Answer: (i) Biomagnification : It is defined as increase in concentration of toxicants at successive trophic levels.
(ii) Eutrophication : Nutrient enrichment of its water.

Short Answer Type Questions

Question 16. Name any two sources of electronic wastes. Mention any one way each of its disposal in developing and developed countries.
Answer: Irreparable computers electronic goods are known as e-wastes. In developing countries : recycling of e-wastes involve manual participation thus exposing workers to toxic substances present in e-wastes. In developed countries : half of the e-wastes are exported to developing countries mainly China, India and Pakistan where metals like copper, iron, silicon, nickel and gold are recovered during cycling process.

Question 17. Particulate and gaseous pollutants along with harmless gases are released from thermal power plants.
(i) Name any two harmless gases released.
(ii) Name the most widely used device of removing particulate pollutants from air. Explain how the device is used?

Answer:

(i) O₂ and N₂
(ii) Electrostatic precipitator : It has electrode wires that are maintained at several thousand volts which produce a corona that releases electrons. These electrons attach to dust particles giving them a net negative charge. The collecting plates are grounded and attract the changed dust particles. The velocity of air between the plates must be low enough to allow the dust to fall. Discharge corona Negatively charged wire

Dirty air Clean air

Dust particles Collection plate grounded

Electrostatic precipitator

Question 18. State the causes and effects of thermal pollution.
Answer: Heated waste water from power plants and industries which raises the temperature of water to a harmful level causes thermal pollution. Effect : It speeds up the biodegradation of organic matter which results into ecological imbalance of the river and streams. It eliminates or reduces the number of organisms sensitive to high temperature and may enhance the growth of plants and fish in extremely cold areas only after causing damage to indigenous flora and fauna.

Question 19. Explain two ways of improper resource utilisation that can cause degradation of natural resources.
Answer: Improper resource utilisation practices include:
(i) Human activities like overcultivation unrestricted grazing, deforestation and results in desertification.
(ii) Poor irrigation facilities lead to improper drainage which causes water logging. This draws salt to the surface of the soil. This increased salt content is not good for the growth of crops.

Question 20. Explain joint forest management.
Answer: Joint forest management : It was introduced by the Government of India in 1980 to realise the significance of participation of local communities in protection and management of forests. In return for their services to the forest, communities get benefit of various forest products like fruit, gum, rubber, medicine etc. This helps in conserving forests in a sustainable manner.

Question 21. (a) What is the norm set by Euro II for petrol and diesel vehicles?
(b) Which cities of India to meet Euro IV norms by April, 2010? Which Euro specification are followed in other cities?
Answer: (a) According to Euro II norms sulphur should be controlled at 350 ppm in diesel and 150 ppm in petrol. Aromatic hydrocarbons should be contained at 42% of the concerned fuel.
(b) Delhi, Mumbai, Kolkata, Chennai, Banglore, Hyderabad, Ahmedabad, Pune, Surat, Kanpur and Agra. Other cities of India should comply with Euro III emission norms by 2010.

Long Answer Type Questions

Question 22. The following diagram shows simplified biogeochemical cycle.
Forest fire Plant Burning fossil Respiration fuel wood
(i) Name the compound whose cycle is depicted.
(ii) In what way do vehicles add this compound to the atmosphere?
(iii) What adverse effect does its excess have on the environment?
(iv) Cite an event which depicts this effect in the modern times.
(v) Suggest two ways of reducing this effect.
Answer: (i) CO₂
(ii) Burning of fossil fuel (combustion)
(iii) Global warming
(iv) Melting of polar ice caps, rising sea level
(v) (a) Planting of trees
(b) Cutting down use of fossil fuels.

Question 23. (i) What is good Ozone? Give its location also.
(ii) What unit is used to measure the thickness of ozone layer in air column?
(iii) What damaging effect does it have?
(iv) What is the cause of the above phenomenon?

Answer:

(i) The good ozone is found in the upper part of the atmosphere called the stratosphere, and it acts as shield absorbing UV radiation from the sun,.
(ii) Dobson unit
(iii) It can cause the harmful UV-rays to reach earth surface which has adverse effect on the health of human beings. UV-rays are responsible for mutation, cancer, snow blindness or inflammation of cornea.
(iv) Release of CFCs, depletes the good ozone layer of stratosphere.