Science Class X 1998(CBSE)
You are on questions

General Instructions :
(i)   All questions are compulsary.
(ii) Question number 1 to 10 are very short answer question,carrying 1 mark each.They are to be answered in one or two sentences.
(iii) Question number 11 to 20 are short answer questions,each carrying 2 marks. Answer to them should not exceed 40 words each.
(iv)  Question numbers 21 to 30 are also short answer questions,each carrying 3 marks. Answer to them should not exceed 60 words each.
(v) Question numbers 31 to 33 are long answer questions,each carrying 5 marks. Answer to them should not normally exceed 100 words each.

Q1. Name the device which directly converts solar energy into electrical energy.


Q2. Name the technique of collecting information through a satellite about an object from a distance.


Q3. An engine supplies 12,000 Jourles of energy per minute.How much power is supplied by it?


Q4. Lights from two different sources A and B have wavelengths 0.3 micron and 0.7 micron respectively. Which one of two lights carries more energy per photon?


Q5. Name any two gases whose presence in air causes green-house effect.


Q6. Name the main constituents of common brass.


Q7. Which property of diamond gives it its special shine?


Q8. Boiled milk does not spoil quickly. Why?


Q9. Which one of the following in a food chain will have maximum concentration of harmful chemicals in its body: small fish, Zooplankton, Birds, Phytoplankton.


Q10. A farmer grows rice crop year after year in his field. He notices a gradual decrease in yield. What could be its cause?


Q11. Name the fuel gases formed when (i) steam, and (ii) a restricted amount of air are passed through a bed of red hot coke. Write the names of their combustible components.


Q12. Calculate the power of an engine which can lift 300 Kg of water through a vertical height of 15m in 15 second. (g = 10 m/s²)


Q13. Mention any two differences between chemical and nuclear reaction.


Q14. Kerosene burns in a cooking stove to give a blue flame while it gives a yellow flame when burnt in a lantern. Give reasons for this difference.


Q15. Give two differences between a star and a shooting star


Q16. What is smog? Name any two diseases caused by smog.


Q17. A trivalent metal X is manufactured by the process of electrolysis. It is the most abundant metal in the earth's crust. Identify the metal and state its two uses.


Q18. What is meant by a functional group in an organic compound? Give the structural formulae of the functional groups in (i) Acetic acid and (ii) Ethyl alcohol.


Q19. What is sickle cell anaemia? What is its direct effect?


Q20. Mention the difference between the food habits of organism belong to the first and third trophic levels. Give one example of each of them.


Q21. Describe the construction of a solar cooker. How does it cause a rise in temperature to cook food?


Q22. What are rocket propellants? Mention any two of their important characteristics. Give an example of liquid propellants.


Q23. Name the process involved in the liberation of energy in (i) the sun and (ii) a nuclear reactor. Mention any two differences between the two processes.


Q24. The mass of a star A is one tenth that of star B. If the mass of A is nearly equal to that of the sun, which one of the two stars will end up as supernova? What would happen to the other star at the end of red giant phase?


Q25. Define isomerism. Write the structural formulae and the names of the isomers of butane.


Q26. Describe any three ways in which the water is important for the activities of living beings.


Q27. A cow is being fed on straw, oil cake, oilseeds, gram and bajra. To what classes of cattle feed do these items belong and what is their importance?


Q28. Moisture content of four food items P, Q, R and S is 10%, 15%, 25% and 50% respectively. Which of these require cold storage and which ones dry storage? Give reasons.


Q29. Name the radiations absorbed by the ozone layer. Give any two causes of the depltetion of ozone layer. Name the disease likely to be caused due to its depletion.


Q30. What is nitrogen fixation? Mention two points of difference between nitrification and denitrification processes. Name the organism involved in these processes.


Q31. Draw diagram of a nuclear reactor. What is the role of moderators in it? How are nuclear reactors used to generate electricity?


Q32. (I) Describe the steps involved in manufacture of blistor coppor from concentrated copper sulphide ore.
(ii) State the process of obtaining pure coper from blister copper with the help of a labelled diagram.
(iii) Name the elements which are mixed with copper to prepare German silver.


Q33.(i) Name the elements that constitute proteins.
(ii) What are the end products of protien digestion and where are they absorbed.
(iii) Name any three types of protiens found in our body and mention thier functions.