Available Answers

1. 1.

   Choose the correct answer from the given options.

   1. In which layer of the atmosphere is moisture available in sufficient quantities?
      1. mesosphere
      2. ionosphere
      3. exosphere
      4. troposphere
   2. It is the layer of the atmosphere that traps the terrestrial heat and helps the Earth to maintain optimum temperature.
      1. troposphere
      2. stratosphere
      3. exosphere
      4. mesosphere
   3. Which of the following devices release Ozone Depleting Substances (ODS)?
      1. fire extinguisher, LPG cylinder
      2. microwave oven, mobile phone
      3. refrigerator, air conditioner
      4. locomotives, bulldozers
   4. Two statements are given in the question below as Assertion (A) and Reason (R). Read the statements and choose the appropriate option: Assertion (A): Ozone hole lets in UV rays that cause skin cancer and cataract. Reason (R): We must buy ozone-friendly products. Choose the correct option:
      1. A is true but R is wrong.
      2. A is false but R is true.
      3. Both A and R are true but R is not the correct explanation of A.
      4. Both A and R are true and R is the correct explanation of A.
   5. Arrange the following in order of the chemical process of ozone depletion.
      1. Chlorine atom pulls one oxygen atom out.
      2. Free oxygen atom hits one chlorine monoxide.
      3. Free chlorine atom hits one ozone molecule.
      4. UV rays cause chlorine atom to break away from CFC molecule.

   Choose the right sequence from the following:

   1. a., b., c., d.
   2. d., c., a., b.
   3. d., c., b., a.
   4. a., b., d., c.

   6. Choose the incorrect statement regarding reduction of global warming.
      1. Should reduce energy consumption.
      2. Should utilise conventional energy resources.
      3. Should encourage green cities.
      4. Promote electric-run vehicles.
   7. The main objective of the Montreal Protocol was
      1. to increase global forest cover.
      2. to reduce pollution of water bodies.
      3. to lower the production of Ozone Depleting Substances.
      4. to increase consumption of fossil fuels.
   8. The ozone layer helps in
      1. preventing the ultraviolet rays from reaching the Earth.
      2. preserving the optimum temperature of the Earth.
      3. absorbing the polluting gases released by the Earth.
      4. increasing the temperature on the Earth.
2. 2.

   Define atmosphere. Name the different layers of the atmosphere.

3. 3.

   What are ions? Why is their presence in the atmosphere significant?

4. 4.

   How can we replace the ODS-emitting accessories in our daily life and prevent escape of chlorine molecules?

5. 5.

   Why are eco-cities or green cities ideal examples of cities today? Name some green cities of the world.

6. 6.

   Why are renewable sources of energy preferred over fossil fuels? Give two examples of renewable sources of energy.