(b) How does a tube well reclaims a water logged soil?
(c) What is salinity?
(d) How do we reclaim a saline soil?
(e) What is reflex arc?
2. (a) What are the main components of Computer?
(b) State the Steps involved in solving a problem on computer
3. The chemical formula of water is H2O. Why no formula is given to air?
4. (a) What is the composition of air of atmosphere?
(b) How rainbow is formed?
(c) How do plants make their food?
(d) What is the end product of this process?
(e) What is the difference between mixture and compound?
(f) What is the smallest planet of solar system?
5. (a) Why it is easier to push heavy grass mover than to lift it?
(b) Why a bomber does not drop a bomb when it is vertically above the target?
(c) What are the producers and consumers in an ecosystem?
(d) How Heroin is produced?
(e) What is the difference between hard water and heavy water?
6. Fill in the blanks.
(i) Pressure cooker works on the principle that the boiling point of a liquid ______________ with the increase of pressure.
(ii) ______________ is the best conductor of electricity.
(iii) Blood Cells are manufactured by ______________ of the body.
(iv) The smallest organism which causes disease is virus and even smaller is ______________.
(v) Neutron, Positron and Proton have ______________ and ______________ charges respectively.
7. Write short notes on any two of the following.
(d) Process of digestion in human body
8. Define the following.
(v) Vitamin C
(vii) Stainless Steel
(viii) Fats and Oils
9. (a) Explain the difference between a car battery and dry battery cells.
(b) Pepsin and Tripsin
(c) Washing Soda and Caustic Soda
(d) X Rays and Gamma rays
(e) Small pox and Measles
10. Write the scientific principle of the following:
(b) Electric Fuse
11. (i) How can you separate the constituents of a mixture of Iodine, Common salt, and powdered glass?
(ii) What is the difference between telescope and a microscope?
(iii) Under what principle electricity is produced by water held up by a dam?
(iv) What is the duration of day and night in polar region? Explain why?
12. How can steel be manufacture from iron ore? Explain.
13. What are the uses of the following instruments?
(x) Geiger counter