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Question Paper Solutions - Science 2016 - 2017 CBSE Class 10

SubjectScience
Year2016 - 2017 (March)

Alternate Sets

      

Marks: 90
[1]1

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

Chapter: [2] Amazing World of Carbon Compounds
Concept: Important Carbon Compounds - Ethanol
[1]2

When a cell reproduces, what happens to its DNA?

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings
[1]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

Chapter: [5.03] Our Environment
Concept: Components of Eco System - Food Chains and Webs
[2]4

An object is placed at a distance of 30 cm in front of a convex mirror of focal length 15 cm. Write four characteristics of the image formed by the mirror.

Chapter: [3] Natural Phenomena
Concept: Reflection of Light - Image Formation by Spherical Mirrors - Convex Mirror
[2]5

What is meant by biodiversity? List two advantages of conserving forests and wild life.

Chapter: [5.02] Management of Natural Resources
Concept: Natural Resources - Forests and Wild Life - Stakeholders
[2]6

What is meant by biodiversity? List two advantages of conserving forests and wild life.

Chapter: [5.02] Management of Natural Resources
Concept: Natural Resources - Forests and Wild Life - Stakeholders
[3]7

Give the structural formula of ethanol.

Chapter: [2] Amazing World of Carbon Compounds
Concept: Important Carbon Compounds - Ethanol

Write the name and structural formula of the compound obtained when ethanol is heated at 443 K with excess of conc. H2SO4. Also write chemical equation for the reaction stating the role of conc. H2SO4 in it.

Chapter: [2] Amazing World of Carbon Compounds
Concept: Important Carbon Compounds - Ethanol
[3]8

Distinguish between esterfication and saponification reaction with the help of the chemical equations for each. 

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents

State one use of esterfication process.

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents

State one use of saponification process. 

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents
[3]9

Write the number of periods and groups in the Modern Periodic Table.

Chapter: [1] School of Elements
Concept: The Modern Periodic Table

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

Chapter: [1] School of Elements
Concept: The Modern Periodic Table
[3]10

Na, Mg and Al are the elements of the same period of Modern Periodic Table having, one, two and three valence electrons respectively. Which of these elements (i) has the largest atomic radius, (ii) is least reactive? Justify your answer stating reason for each case.

Chapter: [1.05] Periodic Classification of Elements
Concept: Position of Elements and Trends in the Modern Periodic Table
[3]11

Write the importance of sexual reproduction in nature.

Chapter: [5] The Life Cycle
Concept: Sexual Reproduction
[3]12

What is vegetative propagation? 

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Multicellular Organisms - Vegetative Propagation

List two advantages of vegetative propagation.

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Multicellular Organisms - Vegetative Propagation

State two disadvantages of vegetative propagation?

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Multicellular Organisms - Vegetative Propagation
[3]13

List any four methods of contraception used by humans. State in brief two advantages of adopting such preventive methods.

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings
[3]14

How did Mendel explain that it is possible that a trait is inherited but not expressed in an organism?

Chapter: [2.04] Heredity and Evolution
Concept: Rules for the Inheritance of Traits - Mendel’s Contributions
[3]15

How are the areas of study – evolution and classification – interlinked?

Chapter: [2.04] Heredity and Evolution
Concept: Evolution and Classification - Introduction
[3]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.

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Concave Lens

If the numerical value of the power of this lens is 10 D, what is its focal length in the Cartesian system ? 

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Concave Lens
[3]17

State the cause of dispersion of white light passing through a glass prism. How did Newton show that white light of sun contains seven colours using two identical glass prisms. Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the focus of the first prism.

Chapter: [3] Natural Phenomena
Concept: Dispersion by a Prism
[3]18

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'.

Chapter: [5.02] Management of Natural Resources
Concept: Natural Resources - Overview of Natural Resource Management

Name and explain any one way by which the underground water table does not go down further.

Chapter: [5.02] Management of Natural Resources
Concept: Natural Resources - Overview of Natural Resource Management
[5]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.

Chapter: [1.04] Carbon Compounds
Concept: Versatile Nature of Carbon - Saturated and Unsaturated Carbon Compounds
[5]20

List two functions ovary of human female reproductive system.

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings

Write the functions of the following parts in a human female reproductive system : Uterus

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings

Write the functions of the following parts in a human female reproductive system: Fallopian tube

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings

Describe placenta structure.

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings

Describe the function of placenta.

Chapter: [5] The Life Cycle
Concept: Reproduction in Human Beings
[5]21

List three distinguishing features, in tabular form, between acquired traits and the inherited traits.

Chapter: [2.04] Heredity and Evolution
Concept: Evolution - Acquired and Inherited Traits

Why are traits acquired during the life-time of an individual not inherited?

Chapter: [2.04] Heredity and Evolution
Concept: Evolution - Acquired and Inherited Traits
[5]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 : 

S. No. Object-Distance
u (cm)
Image-Distance
v (cm)
1 –100 +25
2 –60 +30
3 –40 +40
4 –30 +60
5 –25 +100
6 –15 +120

(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. 

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Convex Lens
[5]23

 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.

Chapter: [3] Natural Phenomena
Concept: Representation of Images Formed by Spherical Mirrors Using Ray Diagrams - Convex Mirror

Define the radius of curvature of spherical mirrors.

Chapter: [3] Natural Phenomena
Concept: Representation of Images Formed by Spherical Mirrors Using Ray Diagrams - Convex Mirror

Find the nature and focal length of a spherical mirror whose radius of curvature is +24 cm.

Chapter: [3] Natural Phenomena
Concept: Representation of Images Formed by Spherical Mirrors Using Ray Diagrams - Convex Mirror
[5]24

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

Chapter: [3] Natural Phenomena
Concept: Defects of Vision and Their Correction
[1]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

Chapter: [1.04] Carbon Compounds
Concept: Important Carbon Compounds - Ethanoic Acid (Acetic acid)
[1]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

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents
[1]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

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents
[1]28

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 

Chapter: [2.04] Heredity and Evolution
Concept: Heredity - Inherited Traits
[1]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

Chapter: [2] Amazing World of Carbon Compounds
Concept: Versatile Nature of Carbon - Homologous Series
[1]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.

 

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Convex Lens
[1]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

Chapter: [3] Natural Phenomena
Concept: Representation of Images Formed by Spherical Mirrors Using Ray Diagrams - Convex Mirror
[1]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

Chapter: [7] Wonders of Light 2
Concept: Refraction of Light - Refraction Through a Rectangular Glass Slab
[1]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

Chapter: [3] Natural Phenomena
Concept: Dispersion by a Prism
[2]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. 

Chapter: [1.04] Carbon Compounds
Concept: Soaps and Detergents
[2]35

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

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Single Organisms - Fission
[2]36

A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen.  

(a) In which direction-toward or away from the lens, does he move the screen to focus the image?
(b) How does the size of the image change?
(c) How does the intensity of the image change as the flame moves towards the lens?
(d) Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Convex Lens
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