CBSE class X Science Physics Sources of Energy 2007


Q. 1. Which component of sunlight facilitates drying of wheat after harvesting?

Q. 2. Which part of solar radiation stimulates the formation of vitamin D in our bodies?

Q. 3. Name two semiconductor materials or elements used in fabricating solar cells.

Q. 4. Name any one element used in making solar cells. On what property of the element is this use based?

Q. 5. Name the largest component of biogas.

Q. 6. How is slurry left over after generation of biogas in biogas plant used?

Q. 7. What is greenhouse effect?

Q. 8. What is bagasse? What is its use?

Q. 9. What is the value of solar constant?

Q. 10. Name the gas that is added to LPG to detect its leakage.

Q. 11. How is biogas produced?

Q. 12. What is gasohol?

Q. 13. Which hydrocarbon has the highest calorific value?

Q. 14. What is wind energy farm?

Q. 15. What is geothermal energy?

Q. 16. What is visible light? What is its approximate wavelength range?

Q. 17. What is common between the three sites (i) Gulf of Kutch in Gujarat


Q. 18. “Electricity generated by the water stored in a dam can be considered to be another form of solar energy.” Explain describing the series of energy transformations in sequence taking place during the process.

Q. 19. Explain how harmful components of sunlight are prevented from reaching the earth’s surface? Name the group of chemical compounds which may destroy this natural process.

Q. 20. State two disadvantages of using hydrogen gas as a fuel.

Q. 21. Mention any two ways by which water can be used to produce hydroelectricity.

Q. 22. Electricity generated with a windmill is another form of solar energy. Explain.

Q. 23. People living on hills often get sunburns on their skin. Which component of sunlight is responsible for this effect? Why is this effect generally not observed near sea level?

Q. 24. In which form is solar energy stored in oceans? Mention any two forms that could be harnessed to obtain energy in usable form.

Q. 25. For producing electricity, the energy from flowing water is preferred to energy obtained by burning coke. State two reasons for it.

Q. 26. What do you mean by the destructive distillation of wood? What are the substances obtained during the process?

Q. 27. Draw a labelled diagram of an experimental set-up for obtaining charcoal from wood. Name the process involved.

Q. 28. State one important advantage and one important limitation of water energy.


Q. 29. Draw the diagram of the floating gas holder type biogas plant and mark on it the gas outlet.

Q. 30. Name the three forms in which energy from oceans is made available for use. What are OTEC power plants? How do they operate?

Q. 31. Write two advantages of using geothermal technologies for power generation purposes. Name atleast two places where geothermal energy can be used for commercial purposes.

Q. 32. Why is biogas considered superior to animal dung as a fuel? Draw a neat labelled diagram of a biogas plant.

Q. 33. Name a possible fuel of the future that is being produced by the fermentation of sugars. To what use is a mixture of this fuel and petrol being put in some countries? Why is this fuel not being used as a commercial fuel at present?

Q. 34. Name some forms of biomass that are suitable for making biogas. Give two advantages of using biowastes to produce biogas.


Q. 35. Draw a labelled diagram of solar cooker. What purposes are served by the blackened surface, glass cover plate and the mirror in a solar cooker? What would happen if the plane glass mirror of a solar cooker is replaced by a concave glass mirror?

Q. 36. Describe the construction of a box - type solar cooker and show it with the help of a diagram. How is the rise in temperature obtained in this set up? Mention two advantages and two limitations of a solar cooker.

Q. 37. On what principle does a solar water heater operate? Draw a labelled schematic diagram for a solar water heater. The solar constant at a place is 1.4 kW/m2. How much solar energy will be received at this place per second over an area of 5 m2.

Q. 38. What is the basic cause for winds to blow? Name a part of India where wind energy is commercially harnessed. Compare wind power and power of water flow in respect of generating mechanical and electrical energies. What is the hindrance in developing them?

Q. 39. Name the major fuel component of biogas. What are its other combustible components? Draw a simple labelled diagram of a fixed dome - type biogas plant. What is the use of the residual slurry and why?

Q. 40. Why is the sun called the ultimate source of practically “all the energy” on the earth? Which form of energy, if any, can be viewed as an exception to this statement?


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