The green plants in a terrestrial eco-system absorb sunlight that falls on their leaves and convert it into food energy. The percentage of solar radiation absorbed by all green plants for the process of photosynthesis is about
- A.1%
- B.5%
- C.8%
- D.10%
Correct answer
Explanation
The correct answer is A, 1%. Green plants are the producers of a terrestrial ecosystem, and NCERT's Class 10 chapter Our Environment states that they capture about 1 percent of the energy of the sunlight that falls on their leaves and convert it into food energy through photosynthesis. The rest of the sunlight is reflected, passes through the leaf or is lost as heat. This tiny fraction is the base of every food chain, and only about 10 percent of it passes from one trophic level to the next, which is Lindeman's ten percent law; that is why food chains rarely have more than three or four steps and why energy flow in an ecosystem is unidirectional. B, 5%, C, 8%, and D, 10%, are all too high: 10 percent is the share of energy transferred between trophic levels, not the share of sunlight captured by plants, and students often mix up these two numbers. Exam tip: plants capture about 1 percent of sunlight; about 10 percent of energy moves up at each trophic level.
Practice Questions
View allWhich one of the following is not included in the National Air Quality Index?
- A.Sulphur
- B.Nitrogen dioxide
- C.Lead
- D.Methane
Show answer
Methane is not one of the pollutants used to calculate India's National Air Quality Index. The National Air Quality Index was launched in 2014 under the Swachh Bharat Abhiyan and is run by the Central Pollution Control Board.
Read the full explanation →Which one of the following statements about the National Green Tribunal is not correct?
- A.It was set up in the year 2010.
- B.It is involved in effective and expeditious disposal of cases relating to environmental protection and conservation of forests.
- C.It may consider giving relief and compensation for damages to persons and property.
- D.It is bound by the procedures laid down under the Code of Civil Procedure, 1908.
Show answer
The National Green Tribunal is not bound by the Code of Civil Procedure; it is guided by the principles of natural justice.
Read the full explanation →Consider the following statements about National Wildlife Action Plan (NWAP) of India for 2017-2031:
1. This is the Third National Wildlife Action Plan.
2. The NWAP is unique as this is the first time India has recognized the concerns relating to climate change impact on wildlife.
3. The NWAP has ten components.
Which of the statements given above is/are correct?
- A.1 only
- B.1 and 2 only
- C.2 and 3 only
- D.1, 2 and 3
Show answer
The plan for 2017-2031 is India's third National Wildlife Action Plan and the first to deal with the impact of climate change on wildlife, but it has five components, not ten.
Read the full explanation →Which one of the following methods is not suitable for urban rainwater harvesting?
- A.Rooftop recharge pit
- B.Recharge wells
- C.Gully plug
- D.Recharge trench
Show answer
A gully plug is a small check structure built across a natural gully or stream channel in hilly and rural land, so it has no place in a city.
Read the full explanation →The city of Cartagena, which is famous for Protocol on Biosafety, is located in
- A.Colombia
- B.Venezuela
- C.Brazil
- D.Guyana
Show answer
Cartagena is a port city on Colombia's Caribbean coast, where talks on the biosafety protocol were held in 1999. The Cartagena Protocol on Biosafety is a supplementary agreement to the Convention on Biological Diversity of 1992.
Read the full explanation →