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Pre-Board Examination
Science
(Theory) PB-10-2000
SET-I
Time: 3 hrs.
M. Marks : 75
General
Instructions:
(a) All questions are
compulsory.
(b) Marks for each question
are indicated against it.
(c) Question number I to 10
are very short answer type questions carrying I
mark each to be answered is one word or maximum
in one sentence.
(d) Question number II to
20 are short answer type questions, each of 2
marks. Answer may not normally exceed 40 words
each.
(e) Question number 21 to
30 are short answer type questions of 3 marks
each. Answer may not normally exceed 60 words
each.
(f) Question numbers 31 to
33 are long answer type questions carrying 5
marks each, which should be answered is not more
than 100 words each.
Q.1. How much power is
supplied by an engine which supplies 12 KJ of
energy per minute? (1)
Q.2. Name the technique of
collecting information through a satellite about
an object from a distance. (1)
Q.3. Write one major
difference between a star and a shooting star.
(1)
Q.4. A lighter and strong
alloy is required for maiding the bodies of
aircrafts. What should be its constituents?
(1)
Q.5. Which one of the
following will have the highest calorific
value?
CnH2n+2,CnH2n+1COOH,CnH2n, CH2n-2
(1)
Q.6. A utensil made of
brass lost its lustre after few days due to
greenish layer on it. What could be the cause
for this. (1)
Q.7. Give the technical
term for the structural and functional unit
comprising living and nonliving components. (1)
Q.8. What are ecological
pyramids? (1)
Q.9
Namethevitaminwhichissynthesisedintheskinbysunlight
(1)
Q.10. A patient was advised
to take more of butter, yellow vegetables and
fruits in his diet. Which vitamin deficiency has
he been suffering from? (1)
Q.11. What are nuclear
wastes? What are the hazards of nuclear wastes
to living organisms? (2)
Q.12. The plane of the
orbit of a satellite A is vertical to 0°
latitude while that of another satellite B
isvertical to 0° longitude. Which one of
these satellite could be used for television
transmission? What should be the approximate
distance of these satellite from Earth's
ourface? Mention the specific name given to such
type of orbits. (2)
Q.13. Explain how ozone
present in atmosphere is important for
sustaining life on earth. (2)
Q.14. Describe the sequence
of events occuring in the final stages of a
stars life, when the initial mass of the star is
much more than that of the sun. (2)
Q.15. Heat produced on
complete combustion of 0.3 gm ofLPG raises
8°C. Specific heat of water is 4.2
J/g°C. Calculate the calorific value ofLPG.
(2)
Q.16. In what respect does
a true solution differ from a colloidal
solution? How will you test whether a given
solution is a colloidal solution? (2)
Q.17. A testtube contains a
blown coloured liquid whose colourremains
unchanged when ethane is passed through it but
disappear with ethene. Name the brown liquid and
give a chemical equation for its reaction with
ethene. (2)
Q.18. Give one test each to
determine the adulteration of (2) (a) Aigenaone
oil in edible oil (b) Vanaspati is
butter
Q.19. What is nitrification
and denitrification. Give an example of
organisms involved in each of these. (2)
Q.20. Consider the
following food chains: (2)
(a)
Plant—>mice—>
snake—>hawk (b) Plant —> mice
—> hawk
If energy available at
producer level is 200j in which case will hawks
get more energy and by how much. Give
justification in support of your answer. (2)
Q.21. Why is the expansion
stroke of an engine also called as power stroke?
Explain the working of an expansion stroke of
petrol engine with a labelled diagram.
(3)
Q.22. What is Red Shift?
Explain doppler effect? What conclusion is
obtained when doppler effect is applied to the
light coming from galaxies. (3)
Q.23. If 768 KJ of energy
is produced per hour in the nuclear fission
reactor, find out the number of
fissions
that would be taking place
in it in 10 min. (Energy released
perfissionis3.2 x10 -11J)
(3)
Q.24. An ore gave sulphur
dioxide on treatment with dilute acid. Identify
the ore and name the process used to concentrate
the ore. Outline the steps that should be taken
to convert such a concentrated ore into free
metal. (3)
Q.25. How is Rayon
prepared? Why is it called a regenerated fibre?
Give two uses of Rayon. (3)
Q.26. Explain the principle
of processing of Petroleum. Name the product
used as furnace fuel in metallurgical operations
and state the temperature at which this product
is obtained. (3)
Q.27. What happens when
ethene reacts with water in the presence of
phosphoric acid? Give appropriate chemical
equation and name the compound So obtained. De-
scribe the process of obtaining this compound
from sugar. . (3)
Q.28. How do HYV's and
traditional varieties differ in respect of input
and output. (3)
Q.29. Explain the ill
effects of man's activities on (a) Environmental
air and water (b) Ozone layer (c) Unplanned
technological
growth.
(3)
Q.30. Explain in brief four
practices in food preparation which lead to loss
in nutrient value of food. What is food
processing? (3)
Q.31. Define mechanical
equivalent of Heat. Establish the relationship
between the mechanical energy and heat with the
help of a neat labelled diagram. Describe the
experiment briefly. (5)
Q.32. An element belonging
to the VI group of the periodic table is mined
by a special technique. Identic the non-metal.
With the help of a labelled diagram, explain the
method of its extraction. What havens when this
non-metal reacts with concen- trated sulphuric
acid and concentrated nitric acid? Write
chemical equations for the abovereactions.(5)
Q.33. State the two general
factors affecting health. How do chemical
pollution and habit forming oubstances affect
the health of an individual. Explain in brief
with 2 ex- amples of each. What are the four
major reasons for infant mortality.
(5)
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