SCIENCE AND TECHNOLOGY— 2005 (Set I—Delhi)
Q. 1. Give an example of photochemical reactions.
Q. 3. State a reaction in which SO2 acts as an oxidising agent. 1
Q. 4. Where will the image be formed by a concave mirror when an object is placed between the pole and the focus point of the mirror? 1
Q. 5. Which has a higher resistance: a 50 W lamp bulb or a 25 W lamp bulb and how many times? 1
Q. 6. How is plaster of Paris chemically different from gypsum? How may they be interconverted? Write one use of plaster of Paris. 2
Q. 7. Allotropy is a property shown by which class of substances, elements, compounds or mixtures? Give one example of allotropy. 2
Q. 8. Draw diagrams to distinguish between 'equatorial orbit' and 'polar orbit' of artificial satellites of earth. 2
Q. 9. With respect to air the refractive indices of water and benzene are 1.33 and 1.50 respectively. Calculate the refractive index of benzene with respect to water. 2
Q. 10. What is the cause of release of unusually large energies in nuclear fission reactions? How is the energy per fission calculated? 2
Q. 11. (a) State the relation between hydrogen ion concentration of an aqueous solution and its pH.
Q. 12. Explain the following regarding the manufacture of ammonia by Haber's process, the reaction being;
N2(g) + 3H2(g) ^=± 2NH3(g) + heat
(i) This reaction is carried out at a high temperature even though it is an exothermic reaction.
Q. 13. (i) Distinguish between an addition polymer and a condensation polymer.
Q. 14. (a) Write the chemical equation representing the reaction for the preparation of methanal from methanol.
(b) What happens when methanal is mixed with:
H---H-C=O + HCN- à
Write the formulae for the given compounds and name the functional groups present in each of them:
Q. 15. A torch bulb is rated 2.5 V and 750 mA. Calculate (i) its power, (ii) its resistance and (in) the energy consumed if this bulb is lighted for
Q. 16. Name three forms in which energy from oceans is made available for use. What are OTEC power plants? How do they operate? 3
Q. 17. Describe briefly the Big Bang Theory of the origin of universe. 3
Q. 18. (a) Write chemical equations for the reactions involved in obtaining pure alumina from the mineral bauxite which has impurities of iron oxide and silica.
(b) Draw a labelled diagram of the electrolytic tank cell used for the extraction of aluminium from alumina. 5
(b)How will you show that the rusting of iron needs oxygen and moisture at the same time.
Q. 19. (a) Explain the following terms used in relation to defects in vision and corrections provided for them:
(b)What is the maximum magnification obtainable by a simple microscope?
Q. 21. Write the expanded form of the abbreviation AIDS. 1
Q. 22. Why is one arm in sub-metacentric chromosome longer than the other? 1
Q. 23. What is 'Green House Effect'? 1
Q. 24. What is 'eutrophication'? Write its two harmful effects. 2
Q. 26. What is 'translocation'? Why is it essential for plants? Where in plants are the
following synthesized:3 (i) Sugars (it) Hormones
Q. 27. Draw a diagram of human brain and label on it the following of its parts:
Q. 28. Differentiate between 'self pollination' and 'cross pollination'. Describe 'double fertilisation' in plants. 3
Q. 29. What is 'organic evolution'? How do embryological studies provide evidence for evolution? 3
Q. 30. Explain the process of 'photosynthesis' in plants. List four factors which influence this process and describe how each of them affects the rate of the photosynthesis process. 5