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CBSE class 10 Science – All India question paper set 2 2017

CBSE class 10 Science – All India question paper set 2 2017

1.Write the molecular formula of the 2
nd and 3rd member of the homologous series whose first member is ethene.1

2.Newly formed DNA copies may not be identical at times. Give one reason. 1

3.In the following food chain, plants provide 500 J of energy to rats. How
much energy will be available to hawks from snakes ?
Plants ???Rats ???Snakes ???Hawks

4.An object is placed at a distance of 15 cm from a convex lens of focal
length 20 cm. List four characteristics (nature, position, etc.) of the image
formed by the lens.

5.Why is an equitable distribution of resources essential in a society ? List
two forces which are against such distribution.

6.Why must we conserve our forests ? List two factors responsible for
causing deforestation.

7.Write the number of periods and groups in the Modern Periodic Table.
How does the metallic character of elements vary on moving (i) from left
to right in a period, and (ii) down a group ? Give reason to justify your
answer.

Na, Mg and Al are the elements of the 3rd period of the Modern Periodic
Table having group number 1, 2 and 13 respectively. Which one of these
elements has the (a) highest valency, (b) largest atomic radius,
and (c) maximum chemical reactivity ? Justify your answer stating the
reason for each.

9.What happens when
(write chemical equation in each case)
(a) ethanol is burnt in air ?
(b) ethanol is heated with excess conc. H2
SO4
at 443 K ?
(c) a piece of sodium is dropped into ethanol ?

10.Explain esterification reaction with the help of a chemical equation.
Describe an activity to show esterification

11.With the help of two suitable examples, explain why certain experiences
and traits earned by people during their lifetime are not passed on to
their next generations. When can such traits be passed on ?

12.‘‘Evolution and classification of organisms are interlinked.’’ Give reasons
to justify this statement.

13.Reproduction is one of the most important characteristics of living beings.
Give three reasons in support of the statement.

14.Describe reproduction by spores in Rhizopus.

15.List three techniques that have been developed to prevent pregnancy.
Which one of these techniques is not meant for males ? How does the use
of these techniques have a direct impact on the health and prosperity of a
family ?

16.Draw ray diagrams to show the formation of three times magnified
(a) real, and (b) virtual image of an object by a converging lens. Mark the
positions of O, F and 2F in each diagram.

17.What is ‘dispersion of white light’ ? State its cause. Draw a ray diagram
to show the dispersion of white light by a glass prism.

1.(a) Water is an elixir of life, a very important natural resource. Your
Science teacher wants you to prepare a plan for a formative
assessment activity, ‘‘How to save water, the vital natural
resource’’. Write any two ways that you will suggest to bring
awareness in your neighbourhood, on ‘how to save water’.
(b) Name and explain any one way by which the underground water
table does not go down further.

19.(a) A student suffering from myopia is not able to see distinctly the
objects placed beyond 5 m. List two possible reasons due to which
this defect of vision may have arisen. With the help of ray
diagrams, explain
(i) why the student is unable to see distinctly the objects placed
beyond 5 m from his eyes.
(ii) the type of the corrective lens used to restore proper vision
and how this defect is corrected by the use of this lens.
(b) If, in this case, the numerical value of the focal length of the
corrective lens is 5 m, find the power of the lens as per the new
Cartesian sign convention.

20.Analyse the following observation table showing variation of
image-distance (v) with object-distance (u) in case of a convex lens and
answer the questions that follow without doing any calculations :

(a) What is the focal length of the convex lens ? Give reason to justify
your answer.
(b) Write the serial number of the observation which is not correct. On
what basis have you arrived at this conclusion ?
(c) Select an appropriate scale and draw a ray diagram for the
observation at S.No.2. Also find the approximate value of
magnification.

21.(a) If the image formed by a mirror for all positions of the object
placed in front of it is always diminished, erect and virtual, state
the type of the mirror and also draw a ray diagram to justify your
answer. Write one use such mirrors are put to and why.
(b) Define the radius of curvature of spherical mirrors. Find the
nature and focal length of a spherical mirror whose radius of
curvature is + 24 cm.

22.With the help of one example for each, distinguish between the acquired
traits and the inherited traits. Why are the traits/experiences acquired
during the entire lifetime of an individual not inherited in the next
generation ? Explain the reason of this fact with an example.

23.(a) Write the functions of each of the following parts in a human
female reproductive system :
(i) Ovary
(ii) Uterus
(iii) Fallopian tube
(b) Write the structure and functions of placenta in a human female.

24.Why are certain compounds called hydrocarbons ? Write the general
formula for homologous series of alkanes, alkenes and alkynes and also
draw the structure of the first member of each series. Write the name of
the reaction that converts alkenes into alkanes and also write a chemical
equation to show the necessary conditions for the reaction to occur.

 

SECTION B

25.A student requires hard water for an experiment in his laboratory which
is not available in the neighbouring area. In the laboratory there are
some salts, which when dissolved in distilled water can convert it into
hard water. Select from the following groups of salts, a group, each salt of
which when dissolved in distilled water will make it hard.
(A) Sodium chloride, Potassium chloride
(B) Sodium sulphate, Potassium sulphate
(C) Sodium sulphate, Calcium sulphate
(D) Calcium sulphate, Calcium chloride

26. While studying the saponification reaction, what do you observe when
you mix an equal amount of colourless vegetable oil and 20% aqueous
solution of NaOH in a beaker ?
(A) The colour of the mixture has become dark brown
(B) A brisk effervescence is taking place in the beaker
(C) The outer surface of the beaker has become hot
(D) The outer surface of the beaker has become cold

27.When you add a few drops of acetic acid to a test-tube containing sodium
bicarbonate powder, which one of the following is your observation ?
(A) No reaction takes place
(B) A colourless gas with pungent smell is released with brisk
effervescence
(C) A brown coloured gas is released with brisk effervescence
(D) Formation of bubbles of a colourless and odourless gas

2.Study the following ray diagram :


In this diagram, the angle of incidence, the angle of emergence and the
angle of deviation respectively have been represented by
(A) y, p, z
(B) x, q, z
(C) p, y, z
(D) p, z, y

29.A student very cautiously traces the path of a ray through a glass slab for
different values of the angle of incidence (? i). He then measures the
corresponding values of the angle of refraction (? r) and the angle of
emergence (? e) for every value of the angle of incidence. On analysing
these measurements of angles, his conclusion would be
(A) ? i > ? r > ? e
(B) ? i = ? e > ? r
(C) ? i < ? r < ? e
(D) ? i = ? e < ? r

30.Study the given ray diagrams and select the correct statement from the
following :


(A) Device X is a concave mirror and device Y is a convex lens, whose
focal lengths are 20 cm and 25 cm respectively.
(B) Device X is a convex lens and device Y is a concave mirror, whose
focal lengths are 10 cm and 25 cm respectively.
(C) Device X is a concave lens and device Y is a convex mirror, whose
focal lengths are 20 cm and 25 cm respectively.
(D) Device X is a convex lens and device Y is a concave mirror, whose
focal lengths are 20 cm and 25 cm respectively.

31.A student obtains a blurred image of a distant object on a screen using a
convex lens. To obtain a distinct image on the screen he should move the
lens
(A) away from the screen
(B) towards the screen
(C) to a position very far away from the screen
(D) either towards or away from the screen depending upon the
position of the object

32.To perform an experiment to identify the different parts of an embryo of a
dicot seed, first of all you require a dicot seed. Select dicot seeds from the
following group :
Wheat, Gram, Maize, Pea, Barley, Ground-nut
(A) Wheat, Gram and Pea
(B) Gram, Pea and Ground-nut
(C) Maize, Pea and Barley
(D) Gram, Maize and Ground-nut

33.The following vegetables are kept in a basket :
Potato, Tomato, Radish, Brinjal, Carrot, Bottle-gourd
Which two of these vegetables correctly represent the homologous
structures ?
(A) Carrot and Tomato
(B) Potato and Brinjal
(C) Radish and Carrot
(D) Radish and Bottle-gourd

34.A student focuses the image of a candle flame, placed at about 2 m from a
convex lens of focal length 10 cm, on a screen. After that he moves
gradually the flame towards the lens and each time focuses its image on
the screen.
(A) In which direction does he move the lens to focus the flame on the
screen ?
(B) What happens to the size of the image of the flame formed on the
screen ?
(C) What difference is seen in the intensity (brightness) of the image of
the flame on the screen ?
(D) What is seen on the screen when the flame is very close (at about
5 cm) to the lens ?

35.Mention the essential material (chemicals) to prepare soap in the
laboratory. Describe in brief the test of determining the nature
(acidic/alkaline) of the reaction mixture of saponification reaction.

36.Draw in sequence (showing the four stages), the process of binary fission
in Amoeba.

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