# Science All India Set 3 2011-2012 CBSE (English Medium) Class 10 Question Paper Solution

Science [All India Set 3]
Date: March 2012

[1] 1

Write the name and formula of the first member of the carbon compounds having functional group − CHO.

Concept: Nomenclature of Organic Compounds (IUPAC)
Chapter: [0.04] Carbon and its Compounds
[1] 2

State one role of ciliary muscles in the human eye.

Concept: Eye Defect and Its Correction: Myopia Or Near-sightedness
Chapter: [0.11] The Human Eye and the Colourful World
[1] 3

Write the name and formula of a molecule made up of three atoms of oxygen.

Concept: Physical Properties of Metals
Chapter: [0.03] Metals and Non Metals
[1] 4

Name two decomposers operating in our ecosystem.

Concept: Ecosystem
Chapter: [0.15] Our Environment
[2] 5

Why do all the elements of the same group have similar properties?

Concept: The Modern Periodic Table
Chapter: [0.05] Periodic Classification of Elements

Explain why All the elements of a period have different chemical properties.

Concept: The Modern Periodic Table
Chapter: [0.05] Periodic Classification of Elements
[2] 6

An element E has following electronic configuration:

 K L M 2 8 6

(a) To which group of the periodic table does element E belong?

(b) To which period of the periodic table does element E belong?

(c) State the number of valence electrons present in element E.

(d) State the valency of the element E.

Concept: The Modern Periodic Table
Chapter: [0.05] Periodic Classification of Elements
[2] 7

Why is vegetative propagation practiced for growing some types of plant? List two plants which are grown by this method.

Concept: Asexual Reproduction in Plant
Chapter: [0.08] How do Organisms Reproduce?
[2] 8

State the role of placenta in the development of embryo.

Concept: Human Reproductive System
Chapter: [0.08] How do Organisms Reproduce?
[2] 9

To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centre of curvature and focus of a concave mirror.

Concept: Concave Mirror
Chapter: [0.1] Light - Reflection and Refraction
[2] 10

What is the colour of the clear sky during day time? Give reason for it.

Concept: Applications of Scattering of Light
Chapter: [0.11] The Human Eye and the Colourful World
[2] 11

Draw a labeled ray diagram to illustrate the dispersion of a narrow beam of white light when it passes through a glass prism.

Concept: Dispersion of Light Through Prism and Formation of Spectrum
Chapter: [0.11] The Human Eye and the Colourful World
[2] 12

List the products of combustion of fossil fuels. What are their adverse effects on the environment?

Concept: Petroleum
Chapter: [0.16] Sustainable Management of Natural Resources
[2] 13

List three problems which arise due to construction of big dams. Suggest a solution of these problems.

Concept: Water Management (Conservation of Water) - Fresh Water Management
Chapter: [0.16] Sustainable Management of Natural Resources
[3] 14

State the meaning of inherited traits and acquired traits. Which of the two is not passes on the next generation? Explain with the help of an example.

Concept: Evolution
Chapter: [0.09] Heredity and Evolution
[3] 15

How fossils formed ?

Concept: Paleobotany
Chapter: [0.09] Heredity and Evolution

Describe in brief two methods of determining the age of fossils.

Concept: Paleobotany
Chapter: [0.09] Heredity and Evolution
[3] 16

If we pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of F1 generation. If we now self-cross the pea plant of F1 generation, then we obtain pea plants of F2 generation.

(a) What do the plants of F2 generation look like?

(b) State the ratio of tall plants to dwarf plants in F2 generation.

(c) State the type of plants not found in F1 generation but appeared in F2 generation, mentioning the reason for the same.

Concept: Heredity
Chapter: [0.09] Heredity and Evolution
[3] 17

A 5 cm tall object is placed perpendicular to the principle axis of a convex lens of focal length 12 cm. The distance of the object from the lens is 8 cm. Using the lens formula, find the position, size and nature of the image formed.

Concept: Convex Mirror
Chapter: [0.1] Light - Reflection and Refraction
[3] 18

State the types of mirrors used for (i) headlights and (ii) rear view mirror, in cars and motorcycles. Give to justify your answer in each case.

Concept: Spherical Mirrors
Chapter: [0.1] Light - Reflection and Refraction
[3] 19

An old man cannot see objects closer than 1 m from the eye clearly. Name the defect of vision he is suffering from. How can it be corrected? Draw ray diagram for the (i) defect of vision and also (ii) for its correction.

Concept: Eye Defect and Its Correction: Myopia Or Near-sightedness
Chapter: [0.11] The Human Eye and the Colourful World
[3] 20

Name the oxidising agent used for the conversion of ethanol to ethanoic acid. Distinguish between ethanol and ethanoic acid on the basis of (i) litmus test, (ii) reaction with sodium carbonate

Concept: Ethanol
Chapter: [0.04] Carbon and its Compounds
[3] 21

List and explain in brief three methods of contraception.

Concept: Human Reproductive System
Chapter: [0.08] How do Organisms Reproduce?
[3] 22

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.

Concept: Periodic Properties
Chapter: [0.05] Periodic Classification of Elements
[5] 23 | Attempt one of the following
[5] 23.1

List the new Cartesian sign convention for reflection of light by spherical mirror. Draw a diagram and apply these conventions for calculating the focal length and nature of spherical mirror which forms a 1/3 times magnified virtual image of an object placed 18 cm in front of it.

Concept: Sign Convention for Reflection by Spherical Mirrors
Chapter: [0.1] Light - Reflection and Refraction
[5] 23.2

With the help of a ray diagram, state what is meant by refraction of light. State Snell’s law for refraction of light and also express it mathematically.

The refractive index of air with respect to glass is 2/3 and the refractive index of water with respect to air is 4/3. If the speed of light in glass is 2 × 108 m/s, find the speed of light in (a) air, (b) water.

Concept: Refractive Index
Chapter: [0.1] Light - Reflection and Refraction
[5] 24 | Attempt one of the following
[5] 24.1
What are hydrocarbons? Write the general formula of (i) saturated hydrocarbons, and (ii) unsaturated hydrocarbons and draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated?
Concept: Saturated and Unsaturated Carbon Compounds
Chapter: [0.04] Carbon and its Compounds
[5] 24.2

What are detergents chemically? List two merits and two demerits of using detergents for cleansing. State the reason for the suitability of detergents for washing, event in the case of water having calcium and magnesium ions.

Concept: Soap
Chapter: [0.04] Carbon and its Compounds
[5] 25 | Attempt one of the following
[5] 25.1

Distinguish between unisexual and bisexual flowers giving one example of each. Draw a diagram showing process of germination of pollen grains on stigma and label the following parts:

(a) Female germ cell

(b) Male germ cell

(c) Ovary

Concept: Sexual Reproduction in Flowering Plants
Chapter: [0.08] How do Organisms Reproduce?
[5] 25.2

Draw a diagram of human female reproductive system and label the part.

(i) That produces eggs.

(ii) Where fusion of egg and sperm take place.

(iii) Where zygote is implanted.

What happens to human egg when it is not fertilized?

Concept: Human Reproductive System
Chapter: [0.08] How do Organisms Reproduce?
[1] 26

The following figure illustrates binary fission in Amoeba in an incorrect sequence.

The correct sequence is

(A) III, II, IV, I

(B) III, IV, II, I

(C) II, III, IV, I

(D) IV, III, II, I

Concept: Asexual Reproduction in Plant
Chapter: [0.08] How do Organisms Reproduce?
[1] 27

From the following diagrams, select the correct ones showing stages of binary fission in Amoeba:

(A) I, II, III

(B) IV, II, III

(C) V, II, III

(D) IV, I, III

Concept: Asexual Reproduction in Plant
Chapter: [0.08] How do Organisms Reproduce?
[1] 28

Following diagrams were drawn by different student on having seen prepared slides of budding in yeast.

Correct diagrams are

(A) I, II, III

(B) II, III, IV

(C) III, IV, V

(D) I, IV, V

Concept: Asexual Reproduction in Plant
Chapter: [0.08] How do Organisms Reproduce?
[1] 29

In which of the following figures is budding not shown?

(A) I

(B) II

(C) III

(D) IV

Concept: Asexual Reproduction in Plant
Chapter: [0.08] How do Organisms Reproduce?
[1] 30

A student weighed some raisins and recorded the weight as ‘x’. She then soaked the raisins in distilled water. After about 2 hours she removed the raisins, wiped them dry and weighed them again, and recorded that as ‘y’. The percentage of water absorbed by raisins may be determined using the relationship.

(y-x)/yxx100

(y-x)/x xx100

(y-x)/x xx1/100

(y-x)xx100

Concept: Chemical Equation
Chapter: [0.01] Chemical Reactions and Equations
[1] 31

In the experiment for determining the percentage of water absorbed by raisins, we do the final weighing of the raisins after keeping them dipped in water for about one hour. For the accuracy of the result, the extra water from the surface of the soaked raisins is removed by

Rubbing with cotton cloth

Hot air blower

Dry cotton wool

Filter paper

Concept: Chemical Equation
Chapter: [0.01] Chemical Reactions and Equations
[1] 32

On adding 2 mL acetic acid to 2 mL of water in a test tube, it was observed that

(A) a clear and transparent solution is formed

(B) a white precipitate is formed almost immediately

(C) two separate layers were formed

(D) a colourless and odourless gas is evolved

Concept: Ethanoic Acid
Chapter: [0.04] Carbon and its Compounds
[1] 33

On adding acetic acid to sodium hydrogen carbonate in a test tube, a student observes

(A) no reaction

(B) a colourless gas with pungent smell

(C) bubbles of a colourless and odourless gas

(D) a strong smell of vinegar

Concept: Ethanoic Acid
Chapter: [0.04] Carbon and its Compounds
[1] 34

Which one of the following are the correct observations about acetic acid?

(A) It turns blue litmus red and smells like vinegar

(B) It turns blue litmus red and smells like burning sulphur

(C) It turns res litmus blue and smells like vinegar

(D) It turns red litmus blue and has a fruity smell

Concept: Ethanoic Acid
Chapter: [0.04] Carbon and its Compounds
[1] 35

The aqueous solutions of copper sulphate and zinc sulphate appear

(A) blue and green respectively

(B) green and colourless respectively

(C) blue and brown respectively

(D) blue and colourless respectively.

Concept: Types of Chemical Change or Chemical Reaction - Double Displacement Reaction
Chapter: [0.01] Chemical Reactions and Equations
[1] 36

Solutions of copper sulphate, iron sulphate and zinc sulphate are prepared and marked I, II and III respectively. Few pieces of aluminium are added to each solutions. After some time a change will be observe in

(A) I and II

(B) II and III

(C) III and I

(D) All the three

Concept: Types of Chemical Change or Chemical Reaction - Double Displacement Reaction
Chapter: [0.01] Chemical Reactions and Equations
[1] 37

Four students showed the following traces of the path of a ray of light passing through a rectangular glass slab.

The trace most likely to be correct is that of student

(A) I

(B) II

(C) III

(D) IV

Concept: Refraction of Light Through a Rectangular Glass Slab
Chapter: [0.1] Light - Reflection and Refraction
[1] 38

While performing the experiment on tracing the path of a ray of light through a rectangular glass slab, in which of the following experimental set-ups is a student likely to get best results? P1 and P2 are the positions of pins fixed by him.

(A) I

(B) II

(C) III

(D) IV

Concept: Refraction of Light Through a Rectangular Glass Slab
Chapter: [0.1] Light - Reflection and Refraction
[1] 39

If you are to determine to focal length of a convex lens, you should have

(A) a convex lens and a screen

(B) a convex lens and a lens holder

(C) a lens holder, a screen holder and a scale

(D) a convex lens, a screen, holder for them and a scale

Concept: Convex Lens
Chapter: [0.1] Light - Reflection and Refraction
[1] 40

A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see

(A) a very blurred image on the wall opposite to the mirror

(B) an erect and magnified image of the tree in the mirror

(C) no image as the screen has been removed

(D) a highly diminished inverted image of the tree at the focus of the mirror.

Concept: Concave Mirror
Chapter: [0.1] Light - Reflection and Refraction
[1] 41

A student has to determine the focal length of a concave mirror by obtaining the image of a distant object on a screen. For getting best result he should focus

(A) a distant tree or an electric pole

(B) a well-illuminated distant building

(C) well-lit grills of the nearest window

(D) a burning candle laced at the distant edge of the laboratory table

Concept: Concave Mirror
Chapter: [0.1] Light - Reflection and Refraction

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