SECTION – A

1. How is the rate of reaction influenced by: (i)  raising the temperature of reactant   (ii) adding to the reacting mixture a product of reaction without change in volume ?
2. In what situation do we use Fleming's Right Hand Rule?
3. Write the chemical equation for the reaction which takes place when sulphur vapours are passed over red hot iron .
4. What will be the frequency of an alternating current, if its direction changes after 0.01sec?
5. An element reacts with oxygen to form an oxide which dissolves in dilute hydrochloric acid. The oxide formed also turns red litmus blue. Is the element a metal or non – metal? Explain with the help of a suitable example.
6. Name the type of orbits possessed by a communication satellite and a remote sensing satellite. Describe their orbits also.
7. The flow of current in a circular loop of wire creates a magnetic field at its centre. How can existence of this field be detected? State the rule which helps to predict the direction of the magnetic field.
8. Write the balanced chemical equation for the reaction taking place when :        (a)    Dry blue copper sulphate crystals are dropped in concentrated sulphuric acid.    (b)   Steam is passed over red hot iron.

(a)    Identify the compounds A,B and C.

(b)  Write balanced chemical equations to represent the conversion of

(c)    Compound A into compound B.

(d)   Compound A into compound C.          

13. A 40 watt lamp requires a 0.182 A of current at 220 volts while a 60 watt lamp requires a 0.272 A of current at 220 volts. If two lamps of 40 and 60 watt are connected in series with a 220 volt line, how many amperes of current will flow through each lamp?                                OR

Two lamps, one related 100 W at 220 V and the other 60W at 220V , are connected in parallel to a 220V supply line. What current is drawn from the supply line?

14. What is bauxite ? Write the main impurities present in this ore? Briefly describe how this ore is purified.
15. What are the common defects of vision? Discuss briefly and find out how they can be removed by using suitable lenses.
16. (a) Why is sulphuric acid called the “king of chemicals”?

(b) Describe with chemical equations how is sulphuric acid manufactured by “Contact Process”

(i)  Name the chief ore of iron. How is it concentrated?

(ii) Describe the extraction of iron from the concentrated ore with  the help of a labeled diagram of the furnace used.

Write necessary chemical equations representing the chemical changes occurring during the process.

(iii) How is the conversion of iron into iron oxide prevented during the extraction of iron?

17. State any harmful effect of lead present as pollutant in air.
18. What is the function of genes in an organism.
19. (a) Name the type of sex chromosome present in : (i) human male            (ii)  human female

20. Leaves of a healthy potted plants were coated with Vaseline to block the stomata. Will this plant remain healthy for long ? State three reasons for your answer.
21. Who proposed the double helical model of DNA? Mention its important features.
22. (a) Explain the mechanism of gaseous exchange between tissue and blood.

23. State differences between artery, vein and capillary.

OR

24. Describe the circulation of blood through the heart during a heartbeat.