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Pre-Board Examination
Science
(Theory) PB-10-2000
SET-II
Time: 3 hrs.
M. Marks : 75
General Instructions:
(a) A 11 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. Number of neutrons in
the atomic nucleus of an atom of an element of
mass number 239 is 145. What will be the number
of protons in the atomic nucleus of its isotope
of mass number 244? (1)
Q.2. Light from two
different sources A and B have wavelengths 0.3
micron and 0.7 micron respectively. Which
one of the two lights carries more energy per
photon? (1)
Q.3. Name the scale on which
the intensity of an earthquake is measured. What
intensity of an earthquake would he mild? ( 1 )
Q.4. Name the metal which
has lowest thermal conductivity. (1)
Q.5. Name one hydrocarbon
which is used in artificial ripening of fruits.
( 1 )
Q.6. Name one disease caused
by lead poisoning. (1)
Q.7. Give the technical term
for the graphic representation of the tropic
structures in .afoodchain.(1)
Q.8. Chemical wastes rich in
nitrogen are discharged into pond leading to
fish mor- tality. Why. (1)
Q.9. A person drinks only
milk. After a year he has bleeding gums. What is
the cause and name of the deficiency disease.
(1)
Q.10.Giveonetesteachtodetenninetheadulterationof
(a) Vanaspati in Ghee (b) Metanil yellow in dal.
(1)
Q.11. Calculate the power of
an engine which can lift 300 kg of water through
a vertical height of 20 m in 20 s. (g = 10
m/s2). (2)
Q.12. The plane of the orbit
of a satellite A is vertical to 0° latitude
while that of another satellite B is vertical to
00 longitude. Which one of these satellite could
he used for Television transmission? What should
be the approximate distance of these satel-
lites from Earth's surface? Mention the specific
name given to such type of orbits. (2)
Q.13. What is a pulsar? How
is i«. different from a protostar? (2)
Q.14. Explain why
(i)venus(ii) mass cannot retain water on their
surface. (2)
Q.15. Explain the term
homologous series. State the name and formula of
the next higher homologueofHCHO. (2)
Q.16. Given a solution of
substance A how will you test whether it is
saturated or unsatur- ated with respect to A, at
the prevailing temperature? What is observed
when a hot saturated solution of a substance is
allowed to cool. (2)
Q.17. When alcohol is heated
in a test tube the alcohol vapours catch fire at
the mouth of the test tube. Mention any two
important conditions of combustion which are
illus- trated by it. (2)
Q.18. What is biological
fixation? How is it different from
nitrification? Give an example of organism
involved in each of these. (2)
Q.19. Consider the following
food chains: (2) (a) Plant —> mice
—> snake —> hawk (b)
Plant—>mice—>hawk If energy
available at producer level is 100 kJ in which
case will hawks get more energy and by how much.
Give justification in support of your
answer.
Q.20. Explain in brief four
practices in food preparation which lead to loss
in nutrient value of food. (2)
Q.21. Fission
ofoneU-235nucleusreleases3.2x
10""Jofenergy. Calculatethenumber of
fissions required to produce energy at the rate
of 5 MW for a day in a generator? - (3)
Q.22. When does a nuclear
reactor become critical? Briefly explain how
this state is accomplished in a reactor. Name
any substance which can be used as control rods.
(3)
Q.23. Describe the
construction of a solar cooker with a diagram.
How does it cause a rise in temperature to cook
food. What is the range of temperature which is
attained? (3)
Q.24. Compare the following
properties of ethyl alcohol and acetic acid.
(a) Litmus Test (b) Sodium
metal reaction (c) Sodium bicarbonate test (3)
Q.25. Name one calcium
compound each and write its chemical formula.
(3)
(a) Which is used for making
mortar and for white wash
(b) Which is used for making
cement and glass (c) Which is used for
disinfecting drinking water
Q.26. Write the chemical
equation involved to obtain thiokol? Mention any
one use of Thiokol. (3)
Q.27. Complete the following
equations (giving names of important products)
(3)
(a) Fe + H2O (seam)—->
(b) CuFeS2 + O2
--
(c) AI + NaOH+H20—>
Q.28. How are high yielding
varieties of wheat obtained. How do HYV' s and
traditional varieties differ in respect of input
and output. (3)
Q.29. A sample of wheat
grain has more than 18% moisture what steps will
you take before putting it in a godown for
storage and ensure correct moisture content. How
will abiotic factors affect stored wheat grain.
(3)
Q.30. Explain the ill
effects of man's activities on (3)
(a) Environmental air and
water (b) Ozone layer (c) Unplanned
Technological growth
Q.31. 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. (5)
Q.32. Draw a labelled
diagram of the fractional distillation tower
forpetroleum. Mention any two fractions obtained
along with their temperatures. Name any two
constituents of petroleum which are not used as
fuels. (5)
Q.33. State the two general
factors affecting health. How do chemical
pollution and habit forming substances affect
the health of an individual. Explain in brief
with two examples of each. What are the four
major reasons for infant mortality.
(5)
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