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Question Paper Solutions - Science 2017 - 2018 CBSE Class 10

SubjectScience
Year2017 - 2018 (March)

Alternate Sets

   

Marks: 90
[1]1

A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F1 progeny?

Chapter: [2.04] Heredity and Evolution
Concept: Rules for the Inheritance of Traits - Mendel’s Contributions
[1]2

Write the energy conversion that takes place in a hydropower plant.

Chapter: [5.01] Sources of Energy
Concept: Conventional Sources of Energy - Hydro Power Plants
[2]3

A compound 'X' on heating with excess conc. sulphuric acid at 443 K gives an unsaturated compound 'Y'. 'X' also reacts with sodium metal to evolve a colourless gas 'Z'. Identify 'X', 'Y' and 'Z'. Write the equation of the chemical reaction of formation of 'Y' and also write the role of sulphuric acid in the reaction.

Chapter: [1.04] Carbon Compounds
Concept: Versatile Nature of Carbon - Saturated and Unsaturated Carbon Compounds
[2]4

Name one gustatory receptor and one olfactory receptor present in human beings.

Chapter: [2.02] Control and Co-ordination in Animals and Plants
Concept: Human Brain - Involuntary Action

Write a and b in the given flow chart of the neuron through which information travels as an electrical impulse.

Chapter: [2.02] Control and Co-ordination in Animals and Plants
Concept: Animals – Nervous System
[2]5

If the image formed by a spherical mirror for all positions of the object placed in front of it is always erect and diminished, what type of mirror is it? Draw a labelled ray diagram to support your answer.

Chapter: [3] Natural Phenomena
Concept: Reflection of Light - Image Formation by Spherical Mirrors - Convex Mirror
[3]6

Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity

Chapter: [1.01] Chemical Reactions
Concept: Chemical Reactions - Types of Chemical Reactions - Decomposition
[3]7 | Attempt Any One
[3]7.1

2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.

Chapter: [2] The Magic of Chemical Reactions
Concept: Balanced Chemical Equation
[3]7.2

The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses.

Chapter: [1.02] Acids, Bases and Salts
Concept: Chemicals from Common Salt Introduction
[3]8

 Why are most carbon compounds poor conductors of electricity?

Chapter: [1.04] Carbon Compounds
Concept: Bonding in Carbon - Covalent Bond

Write the name and structure of a saturated compound in which the carbon atoms are arranged in a ring. Give the number of single bonds present in this compound.

Chapter: [1.04] Carbon Compounds
Concept: Versatile Nature of Carbon - Saturated and Unsaturated Carbon Compounds
[3]9

Name the hormones secreted by the given endocrine glands and specify one function.

Thyroid

Chapter: [2.02] Control and Co-ordination in Animals and Plants
Concept: Hormones in Animals

Name the hormones secreted by the given endocrine glands and specify one function.

Pituitary

Chapter: [2.02] Control and Co-ordination in Animals and Plants
Concept: Hormones in Animals

Name the hormones secreted by the given endocrine glands and specify one function.

Pancreas

Chapter: [2.02] Control and Co-ordination in Animals and Plants
Concept: Hormones in Animals
[3]10

Write one difference between asexual and sexual mode of reproduction.

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

Which species is likely to have better chances of survival - the one reproducing asexually or the one reproducing sexually? Justify your answer.

Chapter: [5] The Life Cycle
Concept: Sexual Reproduction
[3]11 | Attempt Any One
[3]11.1

State the laws of refraction of light. 

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

Explain the term absolute refractive index of a medium and write an expression to relate it with the speed of light in vacuum.

Chapter: [7] Wonders of Light 2
Concept: Refraction of Light - Refraction Through a Rectangular Glass Slab
[3]11.2

What is meant by a power of a lens? Define its SI unit. 

Chapter: [6] Wonders of Light 1
Concept: Refraction at Spherical Surfaces and by Lenses - Power of a Lens

A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens

Chapter: [6] Wonders of Light 1
Concept: Refraction at Spherical Surfaces and by Lenses - Power of a Lens
[3]12 | Attempt Any One
[3]12.1

Show how would you join three resistors, each of resistance 9 Ω so that the equivalent resistance of the combination is 

1) 13.5 

2) 6 Ω

Chapter: [4.01] Effects of Current
Concept: Resistance of a System of Resistors - Resistors in Parallel
[3]12.2

Write Joule's law of heating.

Chapter: [4] The Electric Spark
Concept: Heating Effect of Electric Current

Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?

Chapter: [4] The Electric Spark
Concept: Electric Power
[3]13

List the factors on which the resistance of a conductor in the shape of a wire depends.

Chapter: [4.01] Effects of Current
Concept: Factors on Which the Resistance of a Conductor Depends

Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason?

Chapter: [4.01] Effects of Current
Concept: Electric Current and Circuit

Why are alloys commonly used in electrical heating devices? Give reason.

Chapter: [4.01] Effects of Current
Concept: Factors on Which the Resistance of a Conductor Depends
[3]14

Students in a school listened to the news read in the morning assembly that the mountain of garbage in Delhi suddenly exploded and various vehicles got buried under it. Several people were also injured and there was traffic jam all around. In the brain storming session the teacher also discussed this issue and asked the students to find out a solution to the problem of garbage. Finally they arrived at two main points -one is self management of the garbage we produce and the second is to generate less garbage at individual level.

1) Suggest two measures to manage the garbage we produce.

2) As an individual, what can we do to generate the least garbage? Give two points.

3) List two values the teacher instilled in his student in this episode.

Chapter: [5.03] Our Environment
Concept: Environment - Managing the Garbage We Produce
[3]15

What is a dam? Why do we seek to build large dams? While building large dams, which three main problems should particularly be addressed to maintain peace among local people? Mention them.

Chapter: [5.02] Management of Natural Resources
Concept: Natural Resources - Water for All - Dams
[5]16

Write the steps involved in the extraction of pure metals in the middle of the activity series from their carbonate ores.

Chapter: [1.03] Metals and Non Metals
Concept: Occurrence of Metals - Extraction of Metals

How is copper extracted from its sulphide ore? Explain the various steps supported by chemical equations. Draw labelled diagram for the electrolytic refining of copper.

Chapter: [1.03] Metals and Non Metals
Concept: Occurrence of Metals - Extraction of Metals
[5]17

The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation or all the three attempts.

Chapter: [1.05] Periodic Classification of Elements
Concept: Early Attempts at the Classification of Elements - Dobereiner’s Triads

Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.

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

State Modern periodic law

Chapter: [1] School of Elements
Concept: The Modern Periodic Table
[5]18 | Attempt Any One
[5]18.1

Mention any two components of blood.

Chapter: [3] Life's Internal Secrets
Concept: Concept of Respiration

Trace the movement of oxygenated blood in the body.

Chapter: [3] Life's Internal Secrets
Concept: Concept of Respiration

Write the function of valves present in between atria and ventricles.

Chapter: [2.01] Life Processes
Concept: Concept of Transportation

Write one structural difference between the composition of artery and veins.

Chapter: [2.01] Life Processes
Concept: Concept of Transportation
[5]18.2

Define excretion

Chapter: [3] Life's Internal Secrets
Concept: Concept of Excretion

Name the basic filtration unit present in the kidney.

Chapter: [3] Life's Internal Secrets
Concept: Concept of Excretion

Draw the well-labelled diagram of the human excretory system

Chapter: [3] Life's Internal Secrets
Concept: Concept of Excretion
[5]19

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

(i) Ovary

(ii) Oviduct

(iii) Uterus

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

Describe in brief the structure of placenta

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]20 | Attempt Any One
[5]20.1

A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.

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

What is atmospheric refraction? Use this phenomenon to explain the following natural events:

Twinkling of stars

Draw diagrams to illustrate your answers.

Chapter: [7] Wonders of Light 2
Concept: Atmospheric Refraction
[5]20.2

Write the function of the following part of the human eye: Cornea

Chapter: [6] Wonders of Light 1
Concept: Concept of Human Eye

Write the function of the following part of the human eye:- iris

Chapter: [6] Wonders of Light 1
Concept: Concept of Human Eye

Write the function of the following part of the human eye: crystalline lens

Chapter: [6] Wonders of Light 1
Concept: Concept of Human Eye

Write the function of the following part of the human eye: ciliary muscles

Chapter: [6] Wonders of Light 1
Concept: Concept of Human Eye

Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an observer on the moon? Justify your answer with a reason.

Chapter: [7] Wonders of Light 2
Concept: Some Natural Phenomena Due to Sunlight
[5]21

State Fleming's left hand rule.

Chapter: [12] Magnetic Effect of Electric Current
Concept: Fleming’s Left Hand Rule

Principle of Electric motor

Chapter: [4.02] Magnetic Effects of Current
Concept: Electric Motor

Explain the function of the following parts of an electric motor.

Armature 

Chapter: [4.02] Magnetic Effects of Current
Concept: Electric Motor

Explain the function of the following parts of an electric motor.

Brushes

Chapter: [4.02] Magnetic Effects of Current
Concept: Electric Motor

Explain the function of the following parts of an electric motor.

Split ring

Chapter: [4.02] Magnetic Effects of Current
Concept: Electric Motor
[2]22

A student added few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, she added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate.

In which test tube or test tubes will she observe colour change? On the basis of this experiment, state which one is the most reactive metal and why.

Chapter: [1] Understanding Metals and Non-Metals
Concept: Metals and Nonmetals - Chemical Properties of Metals - Reactivity Series
[2]23

What is observed when a solution of sodium sulphate is added to a solution of barium chloride taken in a test tube? Write equation for the chemical reaction involved and name the type of reaction in this case.

Chapter: [1.01] Chemical Reactions
Concept: Chemical Reactions - Types of Chemical Reactions - Double Displacement
[2]24

List the steps of preparation of temporary mount of a leaf peel to observe stomata.

Chapter: [3] Life's Internal Secrets
Concept: Nutrition - Autotrophic Nutrition
[2]25 | Attempt Any One
[2]25.1

Name the process by which an Amoeba reproduces. Draw the various stages of its reproduction in a proper sequence.

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Single Organisms - Fission
[2]25.2

A student in viewing under a microscope a permanent slide showing various stages of asexual reproduction by budding in yeast. Draw diagrams of what he observes (in proper sequence)

Chapter: [5] The Life Cycle
Concept: Reproduction - Modes of Reproduction Used by Single Organisms - Budding
[2]26

An object of height 4.0 cm is placed at a distance of 30 cm from the optical centre 'O' of a convex lens of focal length 20 cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre 'O' and principal focus 'F' on the diagram. Also find the approximate ratio of size of the image to the size of the object.

Chapter: [3] Natural Phenomena
Concept: Refraction of Light - Image Formation by Lenses - Convex Lens
[2]27

The values of current (I) flowing through a given resistor of resistance (R), for the corresponding values of potential difference (V) across the resistor are as given below:

V (volts) 0.5 1.0 1.5 2.0 2.5 3.0 4.0 5.0
 I (amperes) 0.1 0.2 0.3 0.4 0.5 0.6 0.8 1.0

Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.

Chapter: [4.01] Effects of Current
Concept: Electric Potential Difference
S