MODEL QUESTION PAPER MARCH/APRIL, EXAMINATION 2008 SCIENCE CLASS X (THEORY) TIME : 3 HOURS Max . Marks: 80 _____________________________________________________________________ General Instructions: 1. The question paper comprises of 2 sections A and B. You have to attempt both the sections. 2. All questions are compulsory. 3. Each section consist of 4 questions sets carring 10 marks each. 4. There is no overall choice however internal choice has been provided in two questions of 3 marks category and two questions of 4 marks category in section A and B. You are to attempt only one option in such questions. 5. Begin each set on a fresh page. 6. Figures to the right indicate full marks. SECTION A Set 1.0 1.1: Select the most correct alternative given below each statement and write the completed statement. 1 A: A solution turns red litmus paper blue then its pH value should be ______ Equal to 7 Less than 7 More than 7 Between 0 to 7. B: A solution which is used as a food ingredient is not allowed to put in a copper vessel. Then the solution should be ------------- An acid An alkali. A salt Milk 1.2: What do you mean by an endothermic reaction? 1 1.3: Write any two limitations of Mendeleev’s Periodic Table. 1 1.4: You are given two fuse wires A and B with current rating 5 A and 15A respectively. A: Which of the two would you select for use with 3000 W, 220 V electric geyser? B: Justify your answer. 2 1.5: Combination reaction is said to be opposite of decomposition reaction. Justify it with examples and reactions. 2 1.6: A person suffers from stomach pain and irritation. Doctor prescribes him tablets containing a mixture of Magnesium and Aluminium hydroxides. Answer the questions: 3 A. What is the cause of stomach pain and irritation? B. How will the tablets affect the cause? C. Name any other easily available salt that can be used in place of the tablets prescribed by the doctor. OR 1.6 : A white powder which smells of chlorine readily loses chlorine on exposure to air. It is also used for disinfecting drinking water. Answer the questions: 3 A. Identify white powder compound. B. Write its molecular formula. C. State another use of the compound. Set: 2.0 2.1: Select the most correct alternative given below each statement and write the completed statement. 1 A: The process of removing the gangue from the ore is called------------------. Roasting Calcination. Enrichment. Refining. B. The element named by Mendeleev as Eka-Boron was later discovered and it is called-------------- . Gallium Germanium Sodium Scandium. 2.2: A boy prepares a toy cinema projector. He uses a lens of focal length of 20 cm. He keeps the screen at a distance of 2 meters. A: Name the type of lens used by the boy. B: Calculate and find out, at what distance he should keep the film from the lens to get a clear and sharp image on the screen. 2 2.3: An element X gives a basic oxide and its formula is given as XO. Answer the question: 2 A. Which group will you place it? B. Justify your answer. 2.4: Fe2 O3 + Al → A12 O3 + Fe 2 A. Balance the equation. B. Name the substance that is oxidized in the above reaction and justify your answer in a few words. 2.5 The extraction of metals depends on the reactivity of the metals. Metals of middle order of reactivity series are either roasted or calcinated and then reduced. Answer the following questions. 3 A. What is roasting? B. What is difference between roasting and calcination? C. Arrange the metals Iron, Calcium and Magnesium in order of decreasing reactivity. OR 2.5 See the reactions: 3 Calcium reacts with water Iron reacts with steam. Magnesium reacts with hot water. Sodium reacts with cold water. Answer the following questions: A. Which of the above reaction is most vigorous? B. Which of the above metals shows lowest reactivity with water? C. Arrange the above metals in order of decreasing reactivity. Set: 3.0 3.1: Select the most correct alternative given below each statement and write the completed statement. 1 A: The blue sky is due to---------------------- . Reflection of light. Refraction of light. Scattering of light. Dispersion of light. B: If there was no atmosphere on the earth then_______________ . The sunrise would have been early. The sunrise would have been late. The sunset would have been late. There would be no change. 3.2: A convex mirror and a plane mirror both give erect and virtual images behind the mirrors. But convex mirror is used in automobiles to see the rear view. What is the advantage of the convex mirror over the plane mirror? 1 3.3: Define the Principal Focus of a concave mirror. 1 3.4 Electric appliances, that have a metallic body, are connected to the electric supply by a cable consisting of three wires having insulation covers Red, Black and Green in colours. Answer the questions: 3 A: What do you call Red and Green insulated wires? B: How does the green colour wire work as a safety measure? C: When does an electric short circuit occur? 3.5 : Draw a neat scientific diagram of Human Eye and; 4 A: Label and write the function of Iris. B: Name the defect of an eye that occurs due to decrease of power of accommodation. C: Name the type of lens used to correct the above defect. OR 3.5; A person is unable to see the object beyond 3 meters clearly. 4 Answer the following questions: A: Name the defect of vision he is suffering from. B: List two causes due to which this defect may arise. C: Draw a ray diagram to show correction of this defect using appropriate lens. D: Name the type of lens used to correct the defect. Set: 4.0 4.1: Observe the correlation in the first pair and complete the second pair. 1 A: Unit of electric charge:: coulomb: Unit of electric current: ------- . B: Electric fan: Magnetic effect of electric current:: Electric geyser: --------------- 4.2: Define the power of a lens. 1 4.3: The refractive indices of diamond. glass, kerosene and water are 2.4, 1.5 1.4 and 1.3 respectively. 1 Answer the questions: A: In which substance the speed of the light will be fastest? B: In which substance the bending of light will be maximum? 4.4: See the figure: 3 The direction arrow: Answer the questions: A. When the key is closed what will be the direction of the current in the copper wire AB? B. In which direction will the magnetic needle deflect? C. Name the rule used to find the direction of the magnetic needle. 4.5: A. Draw the circuit diagram as described below: 4 Connect a resistor, a battery, an ammeter, a plug key and a voltmeter across the resistor. And answer the following questions: B. If the value of resistor is 15 ohm and the battery gives Potential Difference of 6V, then calculate the current flowing through the circuit. C. A regulator is used to increase and decrease the speed of an electric fan. How does it work? Write in short. OR 4.5 A. Draw the circuit diagram as described below: 4 Connect two resistors in parallel. Connect them with a battery, an ammeter and a plug key. Insert a voltmeter across the parallel resistors. Show the direction of the flow of current in the circuit. And answer the following questions: B: What will be the effective resistance in the above circuit if both the resistors are of 10 ohm each? C: What will be the effective resistance if they are connected in series? SECTION – B SET 5.0 : 5.1 Select and write the most appropriate alternative from those given below each statement and rewrite the completed statement. 1 H │ A) H ─− C ─− H is the structural formula of __________ │ H Ethane Propane Butane Methane B) Covalently bonded molecules have strong bonds within but intercellular forces are ________________ . Big Small Become Big and Small Not present 5.2 Identify and name the Carbon Compounds given below 1 A) C6 H6 B) C6 H14 5.3 State any two differences between the Saturated Hydro-Carbons and Unsaturated Hydro-Carbons. 1 5.4 How is nuclear energy produced? State its use. 2 5.5. A group of student of Std. V visited a nearby public garden and found that the plants around are all green. Teacher informed that green plants has ability to prepare their own food. 2 A) What is the importance of green pigment in the above plants? B) What is the term used for such plants? C) What do we call the above process? 5.6 Draw and explain the formation of oxygen molecule. 3 Set 6.0 6.1 Fill in the blanks and rewrite the completed statement: 1 A) Rhizopus reproduces by ______________ Budding Regeneration Spore Formation Binary Fission B) The human embryo gets nutrition from the mothers blood with the help of special tissue called ____________ Oviduct Uterus Fallopian tube Placenta 6.2 Observe the given figure and answer the questions below: 2 A) State the type of reproduction seen in given figure. B) State two advantages of above reproduction. 6.3 Rajoo observed a datura flower on a roadside datura plant and found that it has male and female parts in the same flower. 3 A) What are such flowers called? B) Name the male part of the flower? C) How are seeds formed? Explain in brief. OR 6.3 On observing the female part of a flower it is found that the lower part is swollen and the top part is sticky. 3 Answer the following questions. A. Name the swollen part? B. Which part grow to seeds? C. What is pollination? D. Why does top part secret sugary secretion? 6.4 A) Draw a neat diagram of sectional view of the human heart and label: Right Auricle, Aorta. 4 B) State the two differences between right ventricle and left ventricle. C) Name the organ in which oxygenation of blood takes place. D) Name the group of organism that have only two chambers to the heart. OR 6.4 A. Draw a neat diagram of human alimentary canal and label: 4 Stomach, large intestine. B. Name the enzymes produced by pancreatic juice that help in digestion of following food components. Protein Emulsified fats. C. State the function of villi in large intestine. SET 7.0 7.1 Fill in the gaps with appropriate alternative given and rewrite the completed statement 1 A) The theory of natural selection was stated by _______________ Charle’s Darwin Harold C. Urey Gregor Johann Mendel Stanley L. Miller B) Fossils dating is done by detecting the ratio of different.___________ Allotropes of the same element Isotopes of the same element. Compounds of the same element. Alloys of the same element. 7.2 We should use iodilised salt in our daily diet. Why? 1 7.3 What are fossils? 1 7.4 A baby girl is born in a family. Family members were not happy with the girl child. They wanted a male child. 3 A) Which pair of sex chromosomes determine the male sex of offspring? B) How many pairs of chromosomes are present in maternal copy of human beings? C) Why is it said that father is responsible for male child? D) State the difference between X chromosomes and Y chromosomes with respect to their size. OR 7.4 The three children of Mr and Mrs. Rakesh are not the same in their characteristics as the parents. 3 A) In which generation the characters will be the same? B) Who suggested the rule of inheritance of traits? C) What is heredity? D) State a difference between dominant trait and recessive trait. 7.5 A) Draw a neat diagram of neuron and label 4 Axon Nucleus B) State two functions of Forebrain. C) Which part of the brain control blood pressure. D) State the function of Spinal Cord. OR 7.5 A) Draw a neat diagram of Human brain and label cerebrum and crantum. 4 B) What are involuntary actions? C) Which part of the brain is responsible for maintaining posture and balance of the body. D) Name the organ that protects spinal cord. SET 8.0 8.1 Select and write the most appropriate alternative from those given below and rewrite the completed statement. 1 A) The major component of Bio gas is _____________ Hexane Methane Ethane Butane B) The non-metal used in solar cell is ____________ Sulphur Phosphorous Silicon Carbon 8.2 Why is the inner surface of solar cooker painted black? 1 8.3 What is the role of decomposer bacteria? 1 8.4 Narmada Bachao Andolan activist protest raising the height of Sardar Sarovar dam on river Narmada. 2 8.5 How is the harvesting of water done by people? 2 8.6 A) Arrange the following given organisms to form a four step food chain. 3 Man, Frog,Plants,Snakes,Grass hopper,Hawk. B) Name the Secondary Consumer in the above food chain. C) In which trophic level does the plant lie? D) The food chain generally consists of only three to four steps. Why?