SCIENCE AND TECHNOLOGY—2005 (Set II—Delhi)
Except for the following questions, all the remaining questions have been asked in Set 1.
Q. 1. Why is much less heat generated in long electric cables than in filaments of electric bulbs? 1
Q. 3. Write the chemical equation for the reaction of hot aluminium with steam. 1
Q. 7. With respect to air the refractive index of kerosene is 1.44 and that for diamond is 2.42. Calculate the refractive index of diamond with respect to kerosene. 2
Q. 9. What justifies sulphuric acid being called the "king of chemicals"? Why does sugar turn black in contact with concentrated sulphuric acid? 2
Q. 13. A torch bulb is rated 5.0 V and 500 rnA. Calculate (i) its power, (ii) resistance and (iii) energy consumed when it is lighted for four hours. 3
Q. 16. (a) Why is ZnO called an amphoteric oxide? Name another amphoteric oxide.
Q. 18. (a) Draw a schematic labelled diagram of a domestic wiring circuit which includes (i) a main fuse (ii) a power meter, (iii) one light point, and (iv) a power plug.
Q. 22. Name the type of chromosome in which one arm is very long and the other is very short. 1
Q. 25. What are 'fabric filters'? Describe their function in controlling pollution of air. 2
Q. 30. List three differences between respiration in plants and respiration in animals. Describe with a labelled diagram how gaseous exchange occurs through root hair in plants. 5