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K69Y1WD
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Marking Scheme
SUMMATIVE ASSESSMENT – I (2014-15)
Science (Class–X)
General
Instructions:
1. The Marking Scheme provides general guidelines to
reduce subjectivity and maintain uniformity. The answers given in the marking
scheme are the best suggested answers.
2. Marking be done as per the instructions provided
in the marking scheme. (It should not be done according to one’s own
interpretation or any other consideration).
3. Alternative methods be accepted. Proportional
marks be awarded.
4. If a question is attempted twice and the candidate
has not crossed any answer, only first attempt be evaluated and ‘EXTRA’ be
written with the second attempt.
5. In case where no answers are given or answers
are found wrong in this Marking Scheme, correct answers may be found and used
for valuation purpose.
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SECTION-A
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1
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By
changing the amount of water in them resulting in swelling or shrinking.
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1
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2
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1
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3
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15
km/h
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1
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4
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(a) Displacement reaction
(b) Combination reaction
(c) Double displacement reaction
(d) Displacement reaction
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2
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5
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Universal
indicator is a mixture of several indicators.
It shows different colours at different concentrations of hydrogen
ions in a solution.
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2
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6
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(i) The air passing through the nostrils and
nasal passage is filtered by thin fine hairs and mucus
(ii) rings of cartilage ensure that the air
passage does not collapse
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2
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7
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This
is because of corrosion. Iron acquires
a dull brown colour due to formation of iron oxide. Copper acquires a green colour due to the
formation of basic copper carbonate.
Silver acquires a black colour due to the formation of silver
sulphide.
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3
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8
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(a) Magnesium burns with a dazzling light
producing white ash of magnesium oxide.
2 Mg1O2
2 MgO
Magnesium is oxidised
(b) Element A is a non-metal because only
non-metals form neutral and acidic oxides.
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3
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9
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In SO212H2S
2H2O13 S
SO2 is reduced to S. Reducing agent is H2S
H2S is oxidised to S. Oxidizing agent is SO2
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3
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10
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Activity
3.8 Page 40 NCERT book
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3
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11
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Fig
6.10 Page 106
NCERT
with correct labellings
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3
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3
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13
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In
the case of single celled organism, no specific organs for taking in food,
exchange of gases or removal of wastes be needed because the entire surface
of the organism is in contact with the environment. But in multicellular organisms all the
cells may not be in direct contact with the surrounding environment.
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3
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14
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If
on bringing one end of the bars close to each other and no attraction /
repulsion, none of them is a magnet.
If
the two bars attract Þ at least one of them is a magnet.
If
the two bars repel Þ both the bars are magnet.
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3
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15
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W5
q V
5 90000 C 3
40 V 5 3.6 3
106 J
Power
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3
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16
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Symbols
of 3 circuit elements
Role
of each element
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3
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17
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(i) Water from the hot regions under the
earth find outlet at the surface. Such
outlets are known as hot spring.
(ii) Very few places are present on earth
where such energy can be exploited.
(iii) It is a renewable/non polluting source
of energy/cost of production less/any correct answer.
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3
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18
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Fossil fuels Solar
energy
•Non-renewable Renewable
•cause pollution Pollution
free
•Need storage and transportation Available everywhere.
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3
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19
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(a) (i) Reduction
with carbon – Zn, Fe, Pb
(ii) Electrolytic reduction – Al, Na
(iii) Reduction with aluminium – Mn
(b) Roasting : Heating of concentrated ore in
excess of air to convert sulphide ore to its oxide.
2ZnS(s)13O2(g)
2ZnO(s) 12SO2(g)
Calcination : Heating of
concentrated ore in limited supply of air to convert carbonate ore to its oxide.
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5
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20
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(a) Balanced chemical equation has an
equal number of atoms of different
elements in the reactants and products. According to law of conservation of mass matter can neither
be created nor destroyed in a
chemical reaction.
(b) (i)
(ii)
(iii)
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5
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21
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Auxin,
Phototropic movement
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5
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22
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● Derivation of relation R5R11R21R3
●
\ R52
V
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5
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23
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It
is the phenomenon of inducing an electric current in a coil or circuit by
changing the magnetic field associated
with it.
Electric
generator and transformer.
Brief
description of inducing current by -
(i) bringing a bar magnet towards the
coil.
(ii) rotating a coil in a magnetic field.
(iii) varying electric current in a
neighbouring coil.
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5
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24
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(a) Heating effect (b) Always
in series with live wire.
(c) Refer fig 13.20 Page 238 NCERT book.
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5
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SECTION - B
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25
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(c)
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1
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26
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(d)
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1
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27
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(a)
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1
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28
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(a)
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1
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29
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(d)
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1
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30
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(a)
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1
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31
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a
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1
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32
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(d) Not photosynthesizing
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1
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33
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(c)
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1
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34
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(i) Hissing Sound (ii) Container
becomes hot .
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2
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35
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A
– Ammeter, B – Resistor, C – Voltmeter, D – Cell/Battery
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2
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36
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Because
stomata present in turgid leaf are open
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2
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ans 12
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-o0o0o0o-
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