SECTION A 1. Breathing on a mirror turns mirror foggy, what phenomenon is responsible for this?  2. What is the major function of cell wall in plant cell?  3. When a carpet is beaten with a stick, dirt comes out of it. Why?  4. (a) Name the two factors on which the buoyant force depends.  (b) State the relationship between the buoyant force on an object and weight of the liquid displaced by it. 5. State any two reasons for plant cells to have large central vacuole.  6. List any four salient features of meristematic tissue. 
7. What is a super saturated solution?
8.Give reason for the following:(a) A wet handkerchief is placed on the forehead of a person suffering from high fever. (b) We often sprinkle water on the road in summer. 
9. (a) Write four differences between true solution and colloidal solution. (b) What is observed when electric current is passed through a colloidal solution?  10. Draw diagrams to show the difference between the structures of the three types of muscles fibres.  (a) List any four characteristics of parenchyma tissue. (b) What is aerenchyma?  Define manures. What are its three different kinds? State two limitations of manures. Write any one function of the following:  (a) Lysosome (b) Golgi apparatus (c) Endoplasmic Reticulum (a) What is mixed cropping? (b) Write any two advantages of mixed cropping.
15. The velocity time graph of a ball of mass 20 g moving along a straight line on a level ground is given below. How much force does the ground exert on the ball to bring it to rest? 
(a) A car accelerates uniformly from 18 kmh-1 to 36 kmh-1 in 5s. Calculate: (i) acceleration (ii) distance covered by the car in that time.  (b) The length of minute hand of a clock is 14 cm. calculate the speed with which the tip of the minute hand moves.  
17. (a) Define the term inertia. Name the quantity that measures it. (b) Which physical quantity corresponds to rate of change of momentum?
18. (a) Two objects of masses M1 and M2 are dropped in vacuum from a height above the surface of Earth (M1 is greater than M2). Which one will reach the ground first and why?  (b) The earth attracts the moon. Does the moon attract the earth? If it does, why does the earth not move towards the moon?  19. A ball thrown up vertically returns to the the thrower after 6s. Find: (a) The velocity with which it was thrown up. (b) The maximum height it reaches. (c) Its position after 4s. (Given g= 9.8 m/s2) 
20(a) How can a saturated solution be made unsaturated? (b) Give any four application of centrifugation. (c)Name the technique used to separate:(i) butter from curd (ii) Salt from sea water
OR (a) How is air separated from its constituents? (b) How are sol, solution and suspension different from each other?
21(a)why does a steam produces more severe burns on the skin as compared to boiling water? (b)Give to reason to justify that:(i) Water at room temperature is a liquid. (ii) An iron almirah is a solid at room temperature. (c) is dry ice the same thing as ordinary ice?  OR 21(a) How does water kept in an earthen pot become quite cold during summer ? (b) Why can we sip hot tea from a saucer faster than from a cup? (c) Why do solids not possess fluidity?  22. (a) Write any two points of difference between manure and fertilizer.  (b) Name two types of fertilizers. (c) How the excessive use of fertilizers harmful? OR (a) Write any three criteria for the selection of crops during mixed cropping. (b) (c) Name any two plant micronutrients. What is hybridization? 
23. (a) If the mass of a body is doubled, what happens to its acceleration when acted upon by the same force?  (b) It is easier to stop a tennis ball than a cricket ball moving with the same speed. Why? (c) A girl of mass 40 kg jumps with a horizontal...