CBSE sample paper1 class x science 2008

http://www.cbseguess.com/-------------------------------------------------------------------------------------------------------www.cbseguess.com Other Educational Portals www.icseguess.com | www.ignouguess.com | www.dulife.com | www.magicsense.com Sample Paper – 2008 Class – X Subject – Science (Theory) Time allowed: 80 minutes] [Maximum Marks: 25 (Topics included: Chapters 1, 6 and 12) General Instructions: 1. Attempt all questions. 2. Do not write anything on the question paper. 3. This paper contains two Sections A and B. Section A carries 16 marks and Section B carries 9 marks. 4. Attempt all questions of a section together. 5. Marks for each question are indicated near it. SECTION A 1. Write the S.I. units of (a) current (b) charge 1 2. A solution of substance ‘Y’ is used for white washing. Identify ‘Y’ and write down its chemical reaction with water. 1 3. Write the mathematical relation between resistance and resistivity. Hence derive the unit of resistivity. 1 4. White silver chloride turns grey in sunlight. Why? 1 5. Why are alloys preferred in making electric irons? 1 6. Calculate the current through an electrical device if 20 electrons pass through it in 1 minute. 1 7. Balance the following chemical reactions: 2 (a) 2223ONOPbONOPb (b) 2432HOFeOHFe 8. Distinguish between combination and decomposition reactions with one example for each. 2 9. An electric bulb is rated 220V, 100W. (a) What is the maximum current that is permitted to flow through the device? (b) Calculate the resistance of the electric bulb. 1+1 http://www.cbseguess.com/-------------------------------------------------------------------------------------------------------www.cbseguess.com Other Educational Portals www.icseguess.com | www.ignouguess.com | www.dulife.com | www.magicsense.com 10. Three resistors 2, 5 and 8 are connected to a 10V DC source as shown in figure. What reading will the ammeter show? 2 11. Complete the following chemical reactions: 2 (a) 2CuClPb (b) 24OCH SECTION B 12. Write the balanced chemical equation for photosynthesis. 1 13. What are the functions performed by lymphatic system in our body? 1 14. Mention the excretory products in plants. 1 15. What is the necessity of a respiratory pigment? Name the respiratory pigment in humans and state its location. 2 16. What is the role of the following in digestion: 2 a. Salivary amylase b. Mucus in stomach 17. Draw a neat labeled diagram of the human heart. How is it different from that of a fish? 2 2 8 5 10V A http://www.cbseguess.com/-------------------------------------------------------------------------------------------------------www.cbseguess.com Other Educational Portals www.icseguess.com | www.ignouguess.com | www.dulife.com | www.magicsense.com ________________________