7. If emission test is required for an LPG run auto rickshaw, the availability of oxygen is moles for combustion of one mole of butane is a) Less than 5 b) Between 8.5 and 9.5 c) Between 9.5 and 10.5 d) More than 10.5 8. In a soap industry the chemist forgets to add sodium chloride during the manufacture of soap, The possible effect is a) Soap cannot be easily separated. b) Chemical composition of soap changes c) Soap will not get required colour d) The solubility of soap increases 9. Borosilicate glass is used to make school laboratory equipments because it a) Is highly transparent b) With stands sudden changes in the temperature and transparent c) Has high refractive index d) Absorbs radiations 10. Using sodium bydroxide as one of the raw materials it is possible to prepare a) Soaps and detergents b) Cement and ceramics c) Glass and plastics d) Cement and glass Fill in the blanks with suitable terms 1X3=3
11. A p-n junction allows current to pass in one direction. This is called ………………… 12. Radar gun works on the principle of …………………………….. 13. The device which converts light energy into electrical energy is …………………… 14. Match the following and write the answers below the questions in the space provided: A Natural gas Butane Benzene Toluene B L.P.G. explosives to detect leakage of LPG emission test Carbon black Perfumes Exhaust gas answer 1 2 3 4
1. 2. 3. 4.
15. A cyclist going round a curve leanes towards the centre of the curve. Give reason. 16. What is a centrifugal Governor? 2
17. What is the colour of the star Betelgeuse? 18. Mention the purpose of using a plane glass sheet in a solar cooker? 19. How does the pressure cooker help in saving energy? 20. Write the balanced chemical equation of the reaction between sodium carbonate and calcium chloride. 21. Write any two factors on which the induced EMF depends. 22. Draw a neat sketch of a D.C. Dynamo 2X9=18
23. What is electromagnetic spectrum? a) Name the electromagnetic radiations which has 1. The lowest frequency and 2. Lowest wavelength 24. Draw a neat a ketch to show the exhaust stroke of an exiemal combustion engine.
25. Give scientific reasons for the following a) Iron articles are electroplated with chromium b) Calcium silicate is a protective layer for the molten iron in the blast fumes c) Copper is not used to prepare Hydrogen in the laboratory d) Ore of copper is not concentrated by hydraulic...