# Science Delhi Set 3 2012-2013 CBSE Class 10 Question Paper Solution

Science [Delhi Set 3]
Date: March 2013

[1]1

Write two reasons responsible for late discovery of noble gases ?

Concept: Periodic Properties
Chapter: [0.013000000000000001] Periodic Classification of Elements
[1]2

List two measures that you would suggest for the better management of water resources.

Concept: Natural Resources - Water for All - Water Harvesting
Chapter: [0.051] Management of Natural Resources
[1]3

“Cell division is a type of reproduction in unicellular organism.” Justify.

Concept: Sexual Reproduction in Flowering Plants
Chapter: [0.022000000000000002] Reproduction
[2]4

Trace the path of sperms from where they are produced in human body to the exterior.

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction

Write the functions of secretions of prostate gland and seminal vesicles in humans.

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction
[2]5

A ray of light falls normally on the surface of a transparent glass slab. Draw a ray diagram to show its path and also mark angle of incidence and angle of emergence.

Concept: Refraction of Light - Refraction Through a Rectangular Glass Slab
Chapter: [0.03] Natural Phenomena
[2]6

List two advantages associated with water harvesting at the community level.

Concept: Natural Resources - Water for All - Water Harvesting
Chapter: [0.051] Management of Natural Resources
[2]7

We often observe domestic waste decomposing in the bylanes of our homes. List four ways to make the residents aware that the improper disposal of wastes is harmful to the environment and also for their own health.

Concept: The Environment - Our Waste to the Environment
Chapter: [0.052000000000000005] Our Environment
[3]8

Complete the following chemical equations: C2H5OH+O2

Concept: Ethanoic Acid
Chapter: [0.011000000000000001] Carbon Compounds

Complete the following chemical equations : C2H5OH("Conc."H_2SO_4)/(443K)>

Concept: Ethanoic Acid
Chapter: [0.011000000000000001] Carbon Compounds

Complete the following chemical equations : C2H5OH + Na →

Concept: Ethanoic Acid
Chapter: [0.011000000000000001] Carbon Compounds
[3]9

Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties.

Concept: Carbon: a Versatile Element - Homologous Series of Carbon Compound
Chapter: [0.011000000000000001] Carbon Compounds
[3]10

The elements Li, Na and K, each having one valence electron, are in period 2, 3 and 4 respectively of modern periodic table.

(i) In which group of the periodic table should they be ?

(ii) Which one of them is least reactive ?

(iii) Which one of them has the largest atomic radius ? Give reason in justify your answer in each case.

Concept: Periodic Classification of Elements
Chapter: [0.013000000000000001] Periodic Classification of Elements
[3]11

Given below are some elements of the modern periodic table. Atomic number of the element is given in parentheses.

A(4), B(9), C(14), D(19), E(20)

(a) Select the element that has one electron in the outermost shell. Also, write the electronic configuration of this element.

(b) Which two elements amongst these belong to the same group? Give reasons for your answer.

(c) Which two elements amongst these belong to the same period? Which one of the two has bigger atomic radius?

Concept: Periodic Properties
Chapter: [0.013000000000000001] Periodic Classification of Elements
[3]12

Write two examples of sexually transmitted diseases caused by virus.

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction

Write two examples of sexually transmitted diseases caused by bacteri.

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction

Explain how the transmission of virus and bacteria diseases be prevented?

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction
[3]13

Name the following : Thread like non-reproductive structures present in Rhizopus.

Concept: Reproduction in Plant - Modes of Reproduction Used by Multicellular Organisms - Spore Formation
Chapter: [0.022000000000000002] Reproduction

Name the following : 'Blobs' that develop at the tips of the non-reproductive threads in Rhizopus.

Concept: Reproduction in Plant - Modes of Reproduction Used by Multicellular Organisms - Spore Formation
Chapter: [0.022000000000000002] Reproduction

Name the following :
Explain the structure and the function of the structures released from the ‘blobs’ in Rhizopus.

Concept: Reproduction in Plant - Modes of Reproduction Used by Multicellular Organisms - Spore Formation
Chapter: [0.022000000000000002] Reproduction
[3]14

"The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it". Draw a flow chart showing determination of sex of a newborn to justify this statement.

Concept: Sex Determination in Humans
Chapter: [0.021] Heredity and Evolution
[3]15

What are fossils ?

Concept: Evolution and Classification - Fossils
Chapter: [0.021] Heredity and Evolution

State fossils importance in the study of evolution with the help of a suitable example.

Concept: Evolution and Classification - Fossils
Chapter: [0.021] Heredity and Evolution
[3]16

An object of height 4 cm is kept at a distance of 30 cm from a concave lens. Use lens formula to determine the image distance, nature and size of the image formed if focal length of the lens is 15 cm.

Concept: Concave Lens
Chapter: [0.03] Natural Phenomena [0.03] Natural Phenomena
[3]17

Mention the types of mirrors used as (i) rear view mirrors, (ii) shaving mirrors. List two reasons to justify your answers in each case.

Concept: Applications of Spherical Mirrors and Lenses
Chapter: [0.03] Natural Phenomena
[3]18

State the difference in colours of the sun observed during sunrise/sunset and noon. Give explanation for each.

Concept: Some Natural Phenomena Due to Sunlight
Chapter: [0.03] Natural Phenomena
[3]19

What is an ecosystem ?

Concept: Concept of Eco-System
Chapter: [0.052000000000000005] Our Environment

List two main components of ecosystem?

Concept: Food Chain
Chapter: [0.052000000000000005] Our Environment

We do not clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why is it so ? Explain.

Concept: Food Chain
Chapter: [0.052000000000000005] Our Environment
[5]20

Draw a sectional view of human female reproductive system and label the following parts :

(i) Where the development of egg occurs.

(ii) Where fertilization takes place.

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction

Describe, in brief, the changes the uterus undergoes

(ii) if zygote is not formed

Concept: Human Reproductive System
Chapter: [0.022000000000000002] Reproduction
[5]21

(a) Identify A, B and C in the given diagram and write their functions.

(b) Mention the role of gamete and zygote in sexually reproducing organisms.

Concept: Sexual Reproduction in Flowering Plants
Chapter: [0.022000000000000002] Reproduction
[5]22

Define the term ‘isomers’.

Concept: Carbon: a Versatile Element - Nomenclature of Carbon Compounds
Chapter: [0.011000000000000001] Carbon Compounds

Draw two possible isomers of the compound with molecular formula C3H6O and write their names.

Give the electron dot structures of the above two compounds.

Concept: Carbon: a Versatile Element - Chains, Branches and Rings of Carbon Compound
Chapter: [0.011000000000000001] Carbon Compounds
[5]23

A person cannot read newspaper placed nearer than 50 cm from his eyes. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length.

Concept: Eye Defect and Its Correction: Myopia Or Near-sightedness
Chapter: [0.03] Natural Phenomena
[5]24

Define the term absolute refractive index. The absolute refractive index of diamond is 2.42. What is the meaning of this statement? Refractive indices of media A, B C and D are given below:

 Media Refractive index A 1.33 B 1.44 C 1.52 D 1.65

In which of these four media is the speed of light (i) minimum and (ii) maximum ?

Find the refractive index of medium C with respect to medium B.

Concept: Refractive Index
Chapter: [0.03] Natural Phenomena
[1]25

Select the correct statements for the process of budding in yeast:

I. A bud arises from a particular region on a parent body.

II. A parent cell divides into two daughter cells, here the parental identity is lost.

III. Before detaching from the parent body a bud may form another bud.

IV. A bud when detaches from the parent body grows into a new individual.

(A) I, II and III

(B) II, III and IV

(C) III, IV and I

(D) IV, I and II

Concept: Reproduction in Plant - Modes of Reproduction Used by Single Organisms - Budding
Chapter: [0.022000000000000002] Reproduction
[1]26

A student after observing a slide showing different stages of binary fission in Amoeba draws the following diagrams. However these diagrams are not in proper sequence:

The correct sequence is:

(A) I, V, IV, III, II

(B) I, III, IV, V, II

(C) I, V, III, IV, II

(D) I, IV, V, III, II

Concept: Reproduction in Plant - Modes of Reproduction Used by Single Organisms - Fission
Chapter: [0.022000000000000002] Reproduction
[1]27

In the figure, the parts marked A, B and C are sequentially:

Concept: Sexual Reproduction in Flowering Plants
Chapter: [0.022000000000000002] Reproduction
[1]28

Study the different conclusions drawn by students of a class on the basis of observations of preserved/available specimens of plants and animals.

I. Potato and sweet potato are analogous organs in plants.

II. Wings of insects and wings of birds are homologous organs in animals.

III. Wings of insects and wings of bats are analogous organs in animals.

IV. Thorns of citrus and tendrils of cucurbita are analogous organs in plants.

The correct conclusions are:

(A) I, and II

(B) II and IV

(C) I and III

(D) III and IV

Concept: Carbon: a Versatile Element - Homologous Series of Carbon Compound
Chapter: [0.011000000000000001] Carbon Compounds
[1]29

You have potato, carrot, radish, sweet potato, tomato and ginger bought from the market in your jute bag. Identify two vegetables to represent the correct homologous structures.

(A) Potato and tomato

(B) Carrot and tomato

(C) Potato and sweet potato

Concept: Evolution and Classification - Tracing Evolutionary Relationships
Chapter: [0.021] Heredity and Evolution
[1]30

Hard water required for an experiment is not available in a school laboratory. However, following salts are available in the laboratory. Select the salts which may be dissolved in water to make it hard for the experiment.

 (1) Calcium Sulphate (2) Sodium Sulphate (3) Calcium Chloride (4) Potassium Sulphate (5) Sodium Hydrogen Carbonate (6) Magnesium Chloride

(A) 1, 2 and 4

(B) 1, 3 and 6

(C) 3, 5 and 6

(D) 2, 4 and 5

Concept: Salts
Chapter: [0.013999999999999999] Acids, Bases and Salts [0.013999999999999999] Acids, Bases and Salts
[1]31

A student prepared 20% sodium hydroxide solution in a beaker containing water. The observations noted by him are given below.

I. Sodium hydroxide is in the form of pellets.

II. It dissolves in water readily.

III. The beaker appears cold when touched from outside.

IV. The red litmus paper turns blue when dipped into the solution.

The correct observations are:

(A) I, II, and III

(B) II, III and IV

(C) III, IV and I

(D) I, II and IV

Concept: Chemicals from Common Salt (Uses of Salt) - Preparation and Uses of Sodium Hydroxide
Chapter: [0.013999999999999999] Acids, Bases and Salts
[1]32

I. When a red litmus paper is dipped into reaction mixture of a saponification reaction, it turns blue and the reaction is exothermic.

II. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is exothermic.

III. When a red litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.

IV. When a blue litmus paper is dipped into reaction mixture of a saponification reaction, its colour does not change and the reaction is endothermic.

Which of the above statements are correct:

(A) I, and II

(B) II and III

(C) III and IV

(D) I and IV

Concept: Chemical Properties of Acids and Bases
Chapter: [0.013999999999999999] Acids, Bases and Salts
[1]33

A student takes 2 mL acetic acid in a dry test tube and adds a pinch of sodium hydrogen carbonate to it. He makes the following observations:

I. A colourless and odourless gas evolves with a brisk effervescence.

II. The gas turns lime water milky when passed through it.

III. The gas burns with an explosion when a burning splinter is brought near it.

IV. The gas extinguishes the burning splinter that is brought near it.

The correct observations are:

(A) I, II, and III

(B) II, III and IV

(C) III, IV and I

(D) IV, I and II

Concept: Ethanoic Acid
Chapter: [0.011000000000000001] Carbon Compounds
[1]34

In an experiment to study the properties of acetic acid a student takes about 2 mL of acetic acid in a dry test tube. He adds about 2 mL of water to it and shakes the test tube well. He is likely to observe that:

(A) the acetic acid dissolves readily in water

(B) the solution becomes light orange

(C) water floats over the surface of acetic acid

(D) acetic acid floats over the surface of water

Concept: Ethanoic Acid
Chapter: [0.011000000000000001] Carbon Compounds
[1]35

A student focussed the image of a distant object using a device ‘X’ on a white screen ‘S’ as shown in the figure. If the distance of the screen from the device is 40 cm, select the correct statement about the device.

(A) The device X is a convex lens of focal length 20 cm.

(B) The device X is a concave mirror of focal length 40 cm.

(C) The device X is a convex mirror of radius of curvature 40 cm.

(D) The device X is a convex lens of focal length 40 cm.

Concept: Convex Lens
Chapter: [0.03] Natural Phenomena [0.03] Natural Phenomena
[1]36

A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?

(A) He should move the mirror away from the screen.

(B) He should move the mirror slightly towards the screen.

(C) He should move the mirror as well as the screen towards the newly selected object.

(D) He should move only the screen towards the newly selected object.

Concept: Applications of Spherical Mirrors and Lenses
Chapter: [0.03] Natural Phenomena
[1]37

Out of the five incident rays shown in the figure find the three rays that are obeying the laws of refraction and may be used for locating the position of image formed by a convex lens:

(A) 1, 2 and 3

(B) 2, 3 and 4

(C) 3, 4 and 5

(D) 1, 2 and 4

Concept: Convex Lens
Chapter: [0.03] Natural Phenomena [0.03] Natural Phenomena
[1]38

Study the following ray diagrams:

The diagrams showing the correct path of the ray after passing through the lens are:

(A) II and III only

(B) I and II only

(C) I, II and III

(D) I, II and IV

Concept: Concave Lens
Chapter: [0.03] Natural Phenomena [0.03] Natural Phenomena
[1]39

While performing the experiment to trace the path of a ray of light passing through a glass prism, four students marked the incident ray and the emergent ray in their diagrams in the manner shown below.

(A) I

(B) II

(C) III

(D) IV

Concept: Dispersion by a Prism
Chapter: [0.03] Natural Phenomena
[1]40

In an experiment to trace the path of a ray of light through a glass prism for different values of angle of incidence a student would find that the emergent ray:

(A) is parallel to the incident ray

(B) perpendicular to the incident ray

(C) is parallel to the refracted ray

(D) bends at an angle to the direction of incident ray

Concept: Dispersion by a Prism
Chapter: [0.03] Natural Phenomena
[1]41

After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below:

 S. No. ∠i ∠i ∠e I 30° 20° 31° II 40° 25° 40° III 50° 31° 49°

The correct observations are:

(A) I and II

(B) II and III

(C) I and III

(D) I, II and III

Concept: Refraction of Light - Refraction Through a Rectangular Glass Slab
Chapter: [0.03] Natural Phenomena
[1]42

Select from the following the best set-up for tracing the path of a ray of light through a rectangular glass slab:

(A) I

(B) II

(C) III

(D) IV

Concept: Refraction of Light - Refraction Through a Rectangular Glass Slab
Chapter: [0.03] Natural Phenomena

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