SECTION: ‘A’
1. Write the atomic number of any two of the following elements.
(a) Ar (b) Si (c) Ca (d) Al
2. Name any two bacterial sexually transmitted diseases.
3. Write any one example of biotic and abiotic component of our ecosystem.
4. Consider a geographical area containing organisms like snake, grasshopper, peacock, grass and frog. Pesticides are sprayed to kill insects in this area. Which organism will contain the maximum amount of pesticides and why? What is this phenomenon known as?
5. (a) For what purpose is the “Khadin” technique used in Rajasthan?
(b) Mention at least two advantages of this technique.
6. “Stars seem higher than they actually are” Explain, why?
7. (a) What happens to the pollen when it is transferred on the stigma?
(b) What happens to ovary and ovule after fertilization?
8. Draw all the possible isomers of pentane and name them.
9. The elements of a period of the periodic table are given below in order from left to right with one of its element missing:
Li Be B C O F Ne
(a) To which period do these elements belong?
(b) One element of this period is missing. Which is the missing element and where should it be placed?
(c) Which one of these elements in this period shows the property of catenation?
(d) Which one of the above elements belongs to the halogen series?
(e) Identify the noble gas.
10. Calcium, Magnesium and Strontium have been but together in the same group of Periodic Table on the basis of their similar chemical properties.
(a) Mention those properties. (Any two)
(b) Out of the three elements, which one will have atom of biggest size and why?
12. There was a boy named Ram in Rahul‟s class who was HIV+ve. All the children in the class neglected him and treated him like a untouchable. But Rahul provided emotional and moral support to him. He tried his level best to convince all his classmates and was successful in doing so. Later on most of the classmates became the friend of Ram and helped him in what so ever manner they could.
(a) How was Ralutl able to convince his classmates?
(b) What moral value did he show?
13. Define analogous and homologous organs. Identify analogous and homologous organs amongst the following:
Wings of an insect, forelimbs of a human, wings of a bat, forelimbs of frog.
14. How is the sex of a new born genetically determined in humans? “In human beings, the statistical probability of getting either a male or female child is 50 : 50”. Justify this statement.
15. (a) State three of the factors that lead to the origin of a new species.
(b) What is the effect of DNA copying which is not accurate on the reproduction process?
(c) Why are acquired traits not inherited?
16. (a) Define power of a lens. Write the S.I unit in which power of lenses is stated?
(b) Which type of lens behaves as a convergent lens and which as a divergent lens?
(c) A convex lens has a focal length of 50cm. Calculate its power.
17. (a) Show the focus of a concave mirror with the help of a neat ray diagram.
(b) Explain why concave mirror is used as shaving mirror?
(c) Explain why convex mirrors are used as rear view mirror in vehicles?
18. (a) What is long sightedness? List its causes.
(b) How can it be corrected? Draw the ray diagram for its correction.
19. (a) Name any 2 traditional water harvesting measures.
(b) What are the advantages of ground water?
20. Answer the following questions -
(a) Write the name of the saturated hydrocarbon having two carbon atoms, Also write its chemical formula.
(b) Define homologous series of a compound. Write the name and formula of next homologue of
(i) C3H8 (ii) CH3OH.
(c) Explain why Carbon form compounds mainly by covalent bonding.
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