CBSE class 10 Science – All India question paper set 1 2017
CBSE class 10 Science – All India question paper set 1 2017
SECTION A
1. Write the molecular formula of the 2 nd and the 3rd member of the homologous series whose first member is methane.
2. When a cell reproduces, what happens to its DNA ?
3.In the following food chain, 100 J of energy is available to the lion. How
much energy was available to the producer ?
Plants —Deer —Lion
4. An object is placed at a distance of 30 cm from a concave lens of focal
length 15 cm. List four characteristics (nature, position, etc.) of the image
formed by the lens.
5. State two advantages of conserving (i) forests, and (ii) wild-life.
6. Explain two main advantages associated with water harvesting at the
community level
7. Write the structural formula of ethanol. What happens when it is heated
with excess of conc. H2
SO4
at 443 K ? Write the chemical equation for the
reaction stating the role of conc. H2
SO4
in this reaction.
8. Distinguish between esterification and saponification reactions with the
help of the chemical equations for each. State one use of each (i) esters,
and (ii) saponification process.
9.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.
10. Na, Mg and Al are the elements of the 3
rd period of the Modern Periodic Table having group number 1, 2 and 13 respectively. Which one of theseelements has the (a) highest valency, (b) largest atomic radius,
and (c) maximum chemical reactivity ? Justify your answer stating the
reason for each.
11.Reproduction is one of the most important characteristics of living beings.
Give three reasons in support of the statement.
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What is vegetative propagation ? State two advantages and two
disadvantages of this method. 3
13.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 ? 3
14. How did Mendel explain that it is possible that a trait is inherited but not
expressed in an organism ? 3
15.‘‘Evolution and classification of organisms are interlinked.’’ Give reasons
to justify this statement.
16.If the image formed by a lens for all positions of an object placed in front
of it is always erect and diminished, what is the nature of this lens ?
Draw a ray diagram to justify your answer. If the numerical value of the
power of this lens is 10 D, what is its focal length in the Cartesian
system ? 3
17.State the cause of dispersion of white light by a glass prism. How did
Newton, using two identical glass prisms, show that white light is made
of seven colours ? Draw a ray diagram to show the path of a narrow beam
of white light, through a combination of two identical prisms arranged
together in inverted position with respect to each other, when it is
allowed to fall obliquely on one of the faces of the first prism of the
combination.
18.(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.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
20. (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.
21. 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.
22.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.
23.(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.
24.(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.
SECTION B
25.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
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.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
2.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
29.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
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.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
33.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
34.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. 2
35.Draw in sequence (showing the four stages), the process of binary fission
in Amoeba. 2
36.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 ?