Science Class X (CBSE)
Sample Paper Set - I

Max Marks : 75
Time allowed : 3 hrs

General Instructions :
(i)   All questions are compulsary.
(ii) Question number 1 to 10 are very short answer question,carrying 1 mark each.They are to be answered in one or two sentences.
(iii) Question number 11 to 20 are short answer questions,each carrying 2 marks. Answer to them should not exceed 40 words each.
(iv)  Question numbers 21 to 30 are also short answer questions,each carrying 3 marks. Answer to them should not exceed 60 words each.
(v) Question numbers 31 to 33 are long answer questions,each carrying 5 marks. Answer to them should not normally exceed 100 words each.

Q.1 What will be the effect of increase in the amount of carbon dioxide in the atmosphere on the average temparature of earth ?
 

Q.2 A chemical factory in a village discharges its waste, rich in nitrogen compounds, into a pond. How will it affect the growth of phytoplanktons?

Q.3 In the following food chain, plants provide 2000 J of energy to Rats. How much energy will be available to Hawks from the snakes?
Plants - Rats - Snakes - Hawks


Q.4 The formulae of two organic acids X and Y are C₁₀H₂₁ COOH and C₁₉H₃₉ COOH. Which of them exists in liquid state at room temperature?
 

Q.5 Why is the outer part of the candle flame blue?
 

Q.6 Fermentation of sugar solution with enzymes is being carried out in a vessel at 20° C - 30° in the presence of air. Which organic compound will be produced in this process?
 

Q.7 A doctor examined a patient and advised him to take more lemon, orange and amla in his diet. Write any two symptoms that the doctor might have noticed in the patient.
 

Q.8 A constellation having seven prominent stars is visible during the winter. Name the constellation.
 

Q.9 An element X on reacting with oxygen forms an oxide X₂O. This oxide dissolves in water and turns blue litmus red. State whether element X is a metal or a non-metal.
 

Q.10 The number of protons in the nucleus of an atom of an element of mass number 238 is 92.What will be the number of neutrons in its isotope of mass number 235?
 
Q.11 Galaxies A and B are x light years apart while C and D are 1.5x light years apart. In which pair will the two galaxies be moving faster away from each other ? Give reasons for your Answer ?
 

Q.12 Why is charcoal considered a better fuel than wood? Give four reasons.
 

Q.13 In textile mills a white substance having a strong smell of chlorine is used to remove yellowness of white clothes. Identify the substance. Hos is it prepared? Write chemical equation of the reaction involved.
 

Q.14 A water pump can lift 500 kg of water to a tank situated at a height of 10 m in 10 s. Calculate The power of the pump. [ g = 10 m/s2].


Q.15 How is an ester prepared in the laboratory? Write its one use in daily life.
 

Q.16 A gardener by mistake has sown seeds of sunflower too deep in a wet fertile soil. How will this practice influence the production of sunflower crop? Give two reasons for your answer.
 

Q.17 Wastes of which of the following two materials is more polluting - polythene or paper? Give reasons for your answer.
 

Q.18 List four conditions for life to exist on a planet.
 

Q.19 What are synthetic detergents? Give one example of a synthetic detergent. Write its two advantages over soaps.


Q.20 What is the principle of working of solar heater ? Write two major drawbacks of all solar heating devices.
 

Q.21 What causes the wind to blow ? Explain the principle of working of a windmill. State two advantages of using wind energy.
 

Q.22 Why does the iron present in the inner core of the earth remain in solid form despite high temperature ? How does our earth act like an engine ?
 
Q.23 An electric meter shows the consumption of one unit of electrical energy for heating 20 kg of water. What would be the rise in temperature of water if the entire electrical energy is used only to heat the water ? (Specific heat of water = 4200 J/kg/°C)
 

Q.24 What are enzymes? Name its substituents. How are some fruits affected by the action of enzymes. Give one method to reduce the activity of enzymes on fruits.

Q.25 With the help of a labelled diagram and necessary chemical equations describe the preparation of methane in the laboratory.
 
Q.26 We do not consume harmful chemicals as such, then how do they enter our body? Which of the two persons is likely to have more concentration of harmful chemicals - a vegetarian or a non-vegetarian? Give reasons.
 

Q.27 Why is replenishment of soil essential? Describe two natural ways of soil replenishment.
 

Q.28 Distinguish between dry heating and wet heating of foodgrains. Write two harmful effects of wet heating.
 

Q.29 Name the three characteristics which describe the orbit of an artificial satellite around the earth. Illustrate them on a diagram. When is a satellite said to be in geostationary orbit ?
 
Q.30 How is energy liberated in the Sun ? What would happen when all the hydrogen in the Sun gets consumed ? Describe the two steps involved.
 

Q.31 What is a balanced diet? How does the balanced diet depend on special needs? Explain with the help of two examples. Why the roughage and water important part of balanced diet. Name two sources of roughage in our diet.
 

Q.32 With the help of labelled diagrams, explain the construction and working of a diesel engine. State any two differences between a petrol engine and a diesel engine.


Q.33 Name the chief ore of iron. What are the three raw materials used in the production of iron from its ore? With the help of a labelled diagram of a blast furance, describe the extraction of iron from its ore. Write the chemical equations of the reactions involved in the furnace.