SCIENCE AND TECHNOLOGY—2004 (Set II— Compartment Delhi)

Except for the following questions, all the remaining questions. have been asked in Set I.

Q. 3. What focal length can be assigned to a plane mirror? 1

Q. 4. Name the chemical which is commonly used in a laboratory for preserving zoological specimens. 1

Q. 5. Define resistivity of a material. 1

Q. 6. Name the monomers of synthetic rubber and neoprene. Give an example of condensation polymerisation. 2

Q. 8. An electric iron draws a current of 0.5 A when the voltage is 200 volts. Calculate the amount of electric charge flowing through it in one hour. 2

Q. 14. State any two points of difference between the polar and the equatorial orbits of artificial satellites. Write one application of each of these types of orbits. 3

Q. 15. An object 4 cm high is placed at a distance of 27 cm in front of a convex lens of focal length 18 cm. Find the position. nature and size, of the image formed. 3
An object 3 cm high is placed at a distance of 10 cm in front of a concave mirror of focal length 20 cm. Find the position, nature and size of the image formed.

Q. 19. a) In Frasch process of digging out sulphur from a deep underground mine, how has it been made possible to lift sulphur from the bed to the surface of the earth?
b) Besides its elemental form, in what compound forms is sulphur found in nature?
c) Write chemical equations to show reactions of sulphur with (i) hot concentrated sulphuric acid and
(ii) heated carbon. 2, 1, 2
(a) Describe the steps involved in preparing propanone from cumene.
(b) Write the chemical equations for the reactions of propanone with (1) NaBH (ii) alkaline solution
of KMnO4 and (iii) hydrogen cyanide gas. 2,3

Q. 23. Define inheritance. 1