Q18 of 40 Page 1

Name and explain any one way by which the underground water table does not go down further.

Underground water can be recharged by rain water harvesting. The technique to capture and store rain water for future use by making special water harvesting structures is called rain water harvesting. There are two ways of rainwater harvesting: Surface run off where rain water that flows away from the surface can be collected and used. Rooftop rainwater harvesting is the technique where rain water from roof tops of the buildings is collected through canals and drains the water to the ground reservoir. This stored water can be used in future.


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17

State the cause of dispersion of white light by a glass prism. How did Newton, using two identical glass prisms, show that white light is made of seven colours? Draw a ray diagram to show the path of a narrow beam of white light, through a combination of two identical prisms arranged together in an inverted position with respect to each other, when it is allowed to fall obliquely on one of the faces of the first prism of the combination.

 18

Water is an elixir of life, a very important natural resource. Your Science teacher wants you to prepare a plan for a formative assessment activity, ‘‘How to save water, the vital natural resource’’. Write any two ways that you will suggest to bring awareness in your neighbourhood, on ‘how to save water’.

 19

Why are certain compounds called hydrocarbons? Write the general formula for homologous series of alkanes, alkenes, and alkynes and also draw the structure of the first member of each series. Write the name of the reaction that converts alkenes into alkanes and also writes a chemical equation to show the necessary conditions for the reaction to occur.

 20

Write the functions of each of the following parts in a human female reproductive system:

(i) Ovary


(ii) Uterus


(iii) Fallopian tube