Q. 1. What is the power of a concave lens of focal length 50 cm? 1
Q. 2. What will be the frequency of an alternating current if its direction changes after every 0.01 s? 1
Q. 3. Choose neutral oxides out of the following:
Carbon monoxide, carbon dioxide, nitrous oxide and sulphur dioxide. 1
Q. 4. Mention the name of the by-product of soap industry. 1
Q. 5. Name two elements that are stored in kerosene. 1
Q. 6. Calculate the amount of charge that would flow in 1 hour through the element of an electric bulb drawing a current of 0.2 A. 2
Q. 7. Draw a labelled diagram of an experimental set-up for obtaining charcoal from wood. Name the process involved. 2
Q. 8. Name the star that appears stationary to us. Why is it so? Name the constellation that helps in location of its position in the night sky. 2
Q. 9. Name any two non-metals which are used in industry. How is each one of them important to us? 2
Q. 10. Differentiate between addition and condensation type of polymers. Give one example of each of them. 2
Q. 11. A grey coloured building material available in powdered form is a mixture of compounds of calcium. Identify the material. Describe the main steps involved in its Mention the purpose of adding gypsum during its manufacture. 3
Q. 12. What is meant by the term ‘pH of a solution? the pH of gastric juices extracted from the stomach of two persons A and B were found to be 1 and 3 respectively. The stomach juice of which person is more acidic? Find the ratio of hydrogen ion concentration in the two samples. 3
Q. 13. Find the position, nature and size of the image formed by a convex lens of focal length 12 cm of an object 3 cm high placed at a distance 20 cm from it. 3
Find the position, nature and size of the image of an object 3 cm high placed at a distance 9 cm from a concave mirror of focal length 18 cm.
Q. 14. Draw the pattern of field lines due to a bar magnet. Mention any two properties of the magnetic field lines. 3
Draw the pattern of lines of force due to magnetic field associated with a current carrying straight conductor. State how the magnetic field produces changes (i) with an increase in current in the conductor and (ii) the distance from the conductor.
Q. 15. With the help of a labelled diagram describe the main steps involved in the enrichment of ores by the process of froth floatation. 3
Q. 16. What happens when sulphur dioxide reacts with
a) sodium hydroxide solution,
b) hydrogen sulphide, and
c) acidified potassium dichromate solution.
Also write the balanced chemical, equation. for the reactions involved. 3
Q. 17. Name two terrestrial two jovian planets Mention any two points of difference between them
Q. 18. With the help of a schematic diagram explain the chain reaction due to fission of uranium nuclei. Explain how moderators and control rods help in controlling chain reaction in a nuclear reactor.
With the help of a diagram describe the construction and working of a box type solar cooker. Write two advantages and two limitations of solar cookers.
Q. 19. a) State the Faraday’s. laws of electrolysis. What does Faraday constant represent?
b) Describe with a labelled diagram the process of electroplating copper on a metallic spoon. 5
Q. 20. Describe the main steps involved in the extraction of iron from its ore. Write appropriate chemical equations for the reactions involved. Name any two places where iron is extracted from its ore in India.
Describe the method of producing ethanol by fermentation process. What happens when ethanol (i) is burnt in air, (ii) reacts with ethanoic acid in the presence of concentrated sulphuric acid and (iii) reacts with alkaline potassium permanganate? Write balanced equations for each reaction.
Q. 21. Name the scientists who proposed double helical model for the structure of DNA. 1
Q. 22. Name the excretory unit of a kidney. 1
Q. 23. Name any two sexually transmitted diseases. 1
Q. 24. What is ‘eutrophication’? Mention its two harmful effects on aquatic life. 2
Mention any four practices that may help in the conservation and protection of the environment.
Q. 25. Write any two points of difference between respiration in plants and respiration in animals. 2
Q. 26. List the components of blood. Mention any four of its functions in the human body. 3
Q. 27. What are vestigial organs? Name any two vestigial organs in human beings and name the organ which is vestigial for us but not in birds. 3
Q. 28. Draw a diagram to show male’ and female reproductive parts of a flower. Label the following parts in it: 3
(i) Ovary (ii) Anther (iii) Stigma (iv) Filament
Q. 29. Mention two main causes of soil erosion. What is its effect on the environment? Write any three ways by which it can be checked. 3
Q. 30. Name the main organs of the human digestive system in the order they participate in the process of digestion. Describe how digestion of carbohydrates and proteins takes place in our body. 5