Available Answers

1. 1.

   Choose the correct answers to the questions from the given options:

   1. What is the main reason Earth is known as the 'Blue Planet'?
      1. It has a large number of rivers and lakes.
      2. About 71 per cent of the Earth's surface is covered with water.
      3. Water vapour is present in the atmosphere.
      4. Groundwater exists in aquifers.
   2. Why is the hydrological cycle important?
      1. It adds new water to the Earth's surface.
      2. It removes excess water from the Earth's surface.
      3. It constantly moves water in the environment, replenishing water supplies.
      4. It converts salt water into fresh water.
   3. Why is irrigation important for successful agriculture in India?
      1. It reduces the need for rainfall.
      2. It allows for the use of saline water in agriculture.
      3. It helps to manage the problem caused by uneven distribution, seasonal nature and uncertainty of rainfall.
      4. It reduces the dependency on groundwater.
   4. Which of the following is NOT an advantage of well irrigation?
      1. Wells can be dug at any convenient place.
      2. It is the cheapest source of irrigation.
      3. Wells can provide unlimited water throughout the year.
      4. It is an independent source of irrigation.
   5. Why is tank irrigation very popular in peninsular India?
      1. The soil in these regions facilitates the digging of tanks.
      2. The regions have a high groundwater table.
      3. The hard impermeable rocks do not allow percolation of water and the undulating surface forms natural depressions to hold rainwater.
      4. Tank irrigation is cheaper than well irrigation in these regions.
   6. Which is an essential requirement for tube well irrigation in the Indo-Gangetic plains?
      1. Availability of surface water throughout the year
      2. High annual rainfall
      3. Regular supply of cheap electricity and abundant groundwater
      4. Presence of hard, impermeable rocks
   7. Why does canal irrigation cause problems such as water logging and erosion?
      1. Because canal water is rich in sediments that add fertility to the fields.
      2. Because the costs of constructing canals are high.
      3. Because the canal water seeps into the soil, leading to water logging and erosion.
      4. because canals are lined with concrete, clay, stone or brick.
   8. Mention one advantage of drip irrigation compared to other irrigation methods.
      1. It ensure water reaches all parts of the field uniformly.
      2. It reduces water evaporation and runoff by delivering water directly to the root.
      3. It is the least expensive method of irrigation in terms of initial setup costs.
      4. It requires no maintenance and is not prone to clogging.
   9. What is a disadvantage of drip irrigation?
      1. It leads to high water wastage through runoff.
      2. It is ineffective in delivering water to the roots of plants.
      3. It may have high initial setup costs and requires proper filtration to prevent pipe clogging.
      4. It is the most expensive method of irrigation in the long run.
   10. Which of the following measures is NOT a practical method for conserving water resources?
       1. Reuse and recycling of water
       2. Large-scale desalination of seawater
       3. Prevention of water pollution
       4. Adoption of water-saving technologies
2. 2.

   Give reasons to explain why water is considered as a resource.

3. 3.

   State three reasons why irrigation is necessary in India.

4. 4.

   Differentiate between Groundwater and Surface water.

5. 5.

   Differentiate between Wells and Tube wells.

6. 6.

   Differentiate between Inundation canals and Perennial canals.