CBSE Guess > Papers > Question Papers > Class X > 2005 > Science > Delhi Set-II

SCIENCE AND TECHNOLOGY—2005 (Set II—Delhi)

SECTION A

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.
(b) What are alkalies? Give one example of alkalies. 3

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.
(b) Why is it necessary to connect an earth wire to electric appliances having metallic covers? 5

SECTION B

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