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Science
Class X 1996(CBSE)
You
are on Questions
Max Marks : 75
Time allowed : 3 hrs
General Instructions
:
(i) All questions
are compulsory.
(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 temperature 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
depite 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.
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