CBSE Science question Paper Class 10 | X science exam paper | CBSE 2009-2010 Science question paper

Here is a question paper Science  for class 1o .Those student who was preparing for this this board this question paper was very help full to you .

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Q1. Why does the Sun appear reddish at Sunrise?
Q2. The refractive index of diamond is 2.42. What is the meaning of this statement in relation to speed of light?

Q3. Copy this figure in your answer-book and show the direction of the light ray after reflection:

Q4. From amongst the metals sodium, calcium, aluminum, copper and magnesium, name the metal
(i) Which reacts with water only on boiling, and
(ii) Another which does not react even with steam.
Q5. Name the gas evolved when dilute HCl reacts with sodium hydrogen carbonate. How is it recognized?
Q6. What happens chemically when quick lime is added to water?
Q7. What is a solenoid? Draw field lines of the magnetic field through and around a current carrying solenoid.
Q8. Explain with the help of a diagram, why a pencil partly immersed in water appears to be bentat the water surface.
Q9. What is meant by water of crystallisation in a substance? How would you show that blue
copper sulphate crystals contain water of crystallisation?
Q10. What is an oxidation reaction? Identify in the following reaction
(i) The substance oxidised and (ii) the substance reduced:
ZnO + C Zn + CO
Q11. (a) Show the formation of Na2O by the transfer of electrons between the combining atoms.
(b) Why are ionic compounds usually hard?
(c) How is it that ionic compounds in the solid state do not conduct electricity and they do so when in molten state?
Q12. What physical and chemical properties of elements were used by Mendeleef in creating his periodic table? List two observations which posed a challenge to Mendeleef’s Periodic Law.
Q13. (a) Draw a diagram to show the formation of image of a distant object by a myopic eye. Howcan such an eye defect be remedied?

(b) State two reasons due to which this eye defect may be caused
(c) A person with a myopic eye cannot see objects beyond a distance of 1.5m. What would be the power of the corrective lens used to restore proper vision?
Q14. In the circuit diagram given below:
Calculate:
(a) the current through each resistor
(b) the total current in the circuit
(c) the total effective resistance of the circuit.
Q15. (a) What is meant by saying that the potential difference between two points is 1 volt? Name a
device that helps to measure the potential difference across a conductor.
(b) Why does the connecting cord of an electric heater not glow hot while the heating element does?
(c) Electrical resistivities of some substances at 20oC are given below:
Silver 1.60´10 -8Wm
Copper 1.62 ´10-8Wm
Tungsten 5.20 ´10-8Wm
Iron 10.0 ´10-8Wm
Mercury 94.0 ´10-8Wm
Nichrome 100 ´10-6Wm
Answer the following questions in relation to them:
(i) Among silver and copper, which one is a better conductor? Why?
(ii) Which material would you advise to be used in electrical heating devices? Why?
OR
(a) Name and instrument that measures electric current in a circuit. Define the unit of electriccurrent.
(b) What do the following symbols mean in circuit diagrams?
(i) (ii)
(c) An electric circuit consisting of a 0.5m long Nichrome wire XY, and ammeter, a voltmeter,four cells of 1.5 V each and a plug key was set up.

(i) Draw a diagram of this electric circuit to study the relation between the potential
difference maintained between the points ‘X’ and ‘Y’ and the electric current flowing
through XY.
(ii) Following graph was plotted between V and I values:
What would be the values of
V
I
rations when the potential difference is 0.8 V, 1.2 V and 1.6
V respectively? What conclusion do you draw from these values?
Q16. (a) Why does carbon form compounds mainly by covalent bonding?
(b) List any two reasons for carbon forming a very large number of compounds.
(c) An organic acid ‘X’ is a liquid which often freezes during winter time in cold countries,
has the molecular formula, C2H4O2. On warming it with ethanol in the presence of a few drops of conscentrated sulphuric acid, a compound ‘Y’ with a sweet smell is formed.
(i) Identify ‘X’ and ‘Y’.
(ii) Write a chemical equation for the reaction involved.
OR
(a) What is a homologous series of compounds? List any two characteristics of a homologous series.
(b) (i) What would be observed on adding a 5% solution of alkaline potassium permanganate solution drop by drop to some warm ethanol taken in a test tube?
(ii) Write the name of the compound formed during the chemical reaction.
(c) How would you distinguish experimentally between an alcohol and a carboxylic acid on the basis of a chemical property?
Q17. Name the largest cell present in the human body.
Q18. Name the tissue which transports soluble products of photosynthesis in a plant.

Q19. How is the increase in demand for energy affecting our environment adversely?
Q20. What is the impotence in India of hydropower plants? Describe how electric energy is
generated in such plants.
Q21. Write two advantages of classifying energy sources as renewable and non-renewable.
Q22 List any two differences between pollination and fertilisaation.
Q23. A man blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O is dominant? Why?
Q24. Define variation in relation to a species. Why is variation beneficial to the species?
Q25. Define ‘hormones’. Name the humane secreted by thyroid. Write its function. Why
Q26. Distinguish between biodegradable and non-biodegradable substances. List two effects of each of them on our environment.
Q27. (a) Draw a diagram depicting Human limitary Canal and label on it, Gall Baldder, Liver and Pancreas.
(b) State the roles of Liver and Pancreas.
(c) Name the organ which performs the following functions in humans:
(i) Absorption of digested food.
(ii) Absorption of water
OR
(a) Draw a sectional view of the human heart and label on it, Aorta, Right Ventricle and Pulmonary Veins.
(b) State the functions of the following components of transport system:
(i) Blood (ii) Lymph

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