NCERT Solutions for
Class 10 Science 2020-21
are prepared by our subject experts in such a way that
the students understand all the topics covered in the syllabus of CBSE
10 science
quite effectively. It also helps you to understand the topic
thoroughly, which is very important not only from the point of Class 10
examination but better understanding lays a great foundation for your
future studies. Quite often, questions
from the textbooks are also asked in competitive examinations. We have
covered both intext and exercise questions in detail.

Science class 10 chapter 1, Class 10 science PDF, Science class 10 notes, Class 10 science syllabus

NCERT solutions for class 10 science chapter 10, NCERT solutions for class 10 science chapter 2

NCERT solutions for class 10 science electricity, NCERT solutions for class 10 science study Rankers

NCERT Solutions Class 10 Science Book All Chapters Details:

SCIENCE CLASS 10 Chapter 1 – Chemical Reactions and Equations

The first chapter of Class 10 NCERT Science will
teach you about chemical reactions and how to write equations, how to
conduct combination and decomposition reactions and more. In the
previous classes, we have learned about physical and chemical changes of
matter. Whenever a chemical change occurs, we can say that a chemical
reaction has taken place. A complete chemical reaction represents the
reactants, products and their physical states symbolically. You will
also study how to write a chemical reaction, which is a symbolic
representation of a chemical reaction. The chapter also explains how
various chemical equations can be balanced in different states.

The next subtopic teaches about various chemical reactions such as
Combination Reaction, Decomposition reaction, Displacement Reaction, and
Double Displacement Reaction along with various examples and chemical
reactions. On the basis of energy, exothermic and endothermic reactions
are explained. Exothermic reactions are those reactions in which heat is
given out along with the products and endothermic reactions are those
reactions in which energy is absorbed. Then redox reaction is explained,
which is a combination of reduction reaction and oxidation reaction.
The chapter explains all types of reactions with suitable examples with
their respective chemical equations.

SCIENCE CLASS 10 Chapter 2 – Acids, Bases and Salts

NCERT Class 10 Science Chapter 2 is all about acids, bases and salts.
In your previous classes, you have learned that the sour and bitter
tastes of food are due to acids and bases, respectively, present in
them. We all know that acids are sour in taste and change the colour of
blue litmus to red, whereas, bases are bitter and change the colour of
the red litmus to blue. In this chapter, we will study the reactions of
acids and bases, how acids and bases cancel out each other’s effects and
many more interesting things that we use in our day-to-day life. You
will get to understand the chemical properties of acids and bases, how
acids and bases react with metals, how do metal carbonates and metal
hydrogen carbonates react with acids, how do acids and bases react with
each other, reaction of metallic oxides with acids and reaction of a
non-metallic oxide with base explained with suitable examples and
various chemical reactions.

The chapter then explains what all acids and bases have in common
with a suitable example which gives the conclusion that acid solution in
water conducts electricity. Students get to learn various experiments
on what happens to acid or a base in a water solution and how strong are
acid or base solutions by making use of universal indication. Along
with it, you will get to learn about the importance of pH in everyday
life. The chapter ends with explaining in detail about salt preparation,
properties and its uses.

SCIENCE CLASS 10 Chapter 3 – Metals and Non-metals

In your previous class, you have learned about various elements that
can be classified as metals or non-metals on the basis of their
properties. Here in Chapter 3 of Class 10 Science, you will learn about
the physical properties of metals and non-metals. Metals are lustrous,
malleable, ductile and are good conductors of heat and electricity. They
are solid at room temperature, except mercury which is a liquid. The
physical properties of metals are explained on various parameters such
as ductility, malleability, tensile, strength, etc. On the basis of
physical properties, metals and non-metals are differentiated. Some of
the examples of non-metals are carbon, sulphur, iodine, oxygen,
hydrogen, etc. The non-metals are either solids or gases except bromine
which is a liquid. Under the subtopic chemical properties of metals,
chemical reactions are discussed with oxygen gas, water, acids and other
metal salts. On the basis of reactivity series the reactions and
conditions depend. The reactivity series tops potassium as the most
reactive and Gold as the least reactive.

The compounds formed in this manner by the transfer of electrons from
a metal to a non-metal are known as ionic compounds or electrovalent
compounds. Some of the general properties for ionic compounds are
physical nature, melting and boiling points, solubility and conduction
of electricity. Metal is extracted from its ore and then refining them
for use is known as metallurgy. Metals are refined by using the method
of electrolytic refining. The end topic explains about corrosion and how
it can be prevented.

SCIENCE CLASS 10 Chapter 4 – Carbon and its Compounds

In the previous chapter, we discuss compounds of importance to us. In
this chapter, we will study some more interesting compounds and their
properties. Also, we shall be learning about carbon, an element which is
of immense significance to us in both its elemental form and in the
combined form. Carbon is a versatile element that forms the basis for
all living organisms and many of the things we use. Covalent bonds are
formed by the sharing of electrons between two atoms so that both can
achieve a completely filled outermost shell. Carbon forms covalent bonds
with itself and other elements such as hydrogen, oxygen, sulphur,
nitrogen and chlorine. Organic compounds are categorized into saturated
and unsaturated carbon compounds. Saturated compounds are compounds with
only a single bond. Unsaturated carbon compounds are compounds with a
double or triple bond. The saturated compounds of carbon and hydrogen
are methane, ethane, propane, butane, pentane and hexane.

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The chapter also explains some of the chemical properties of carbon
compounds such as combustion, oxidation, addition reaction, substitution
reaction. Ethanol and ethanoic acid are carbon compounds of importance
in our daily lives. Soap and detergents are studied with their chemical
structures and properties and their difference is also discussed.
Detergents are usually used to make shampoos and products for cleaning

SCIENCE CLASS 10 Chapter 5 – Periodic Classification of Elements

In Standard 9 we have learned that matter around us is present in the
form of elements, compounds and mixtures and the elements contain atoms
of only one type. The early attempts at the classification of elements
resulted in grouping the then-known elements as metals and non-metals.
Dobereiner grouped the elements into triads and Newlands gave the Law of
Octaves. Mandelvee arranged the elements in increasing order of their
atomic masses and according to their chemical properties. He even
predicted the existence of some yet to be discovered elements on the
basis of gaps in his Periodic table. The modern periodic table came into
existence. Mendeleev’s Periodic Law was modified and the atomic number
was adopted as the basis of the Modern Periodic Table and the Modern
Periodic Law can be stated as follows: ‘Properties of elements are a
periodic function of their atomic number’.

Elements in the Modern Periodic Table are arranged in 18 vertical
columns called groups and 7 horizontal rows called periods. Elements
thus arranged show periodicity of properties including atomic size,
valency or combining capacity and metallic and non-metallic character.
The valency of an element is determined by the number of valence
electrons present in the outermost shell of its atom. The term atomic
size refers to the radius of an atom.

SCIENCE CLASS 10 Chapter 6 – Life Processes

NCERT Class 10 Science Chapter 6 explains life processes. There are
six life processes that all living organisms perform. They are movement,
respiration, growth, reproduction, excretion and nutrition. The chapter
also teaches about nutrition which means the process of taking in food
and using it for growth, metabolism and repair. Nutritional stages are
ingestion, digestion, absorption, transport, assimilation, and
excretion. Nutrition is further divided into Autotrophic Nutrition and
Heterotrophic Nutrition. Autotrophic nutrition involves the intake of
simple inorganic materials from the environment and using an external
energy source like the Sun to synthesize complex high-energy organic
material. Heterotrophic nutrition involves the intake of complex
material prepared by other organisms. Different types of heterotrophic
nutrition are parasitic nutrition, saprophytic nutrition and holozoic
nutrition. The next topic is nutrition in human beings. The various
steps of nutrition are ingestion, digestion, Oesophagus, stomach, small
intestine, bile, absorption, assimilation and egestion. The next
subtopic is respiration in which the human respiratory system is
explained beautifully. The different elements of the human respiratory
system are lungs, bronchi, larynx, pharynx, etc. During the process of
respiration, organic compounds such as glucose are broken down to
provide energy in the form of ATP. ATP is used to provide energy for
other reactions in the cell.

Respiration may be aerobic or anaerobic. Aerobic respiration makes
more energy available to the organism. For plants, the soil is the
nearest and richest source of raw materials like nitrogen, phosphorus
and other minerals. In human beings, the transport of materials such as
oxygen, carbon dioxide, food and excretory products is a function of the
circulatory system. The circulatory system consists of the heart, blood
and blood vessels. In highly differentiated plants, transport of water,
minerals, food and other materials is a function of the vascular tissue
which consists of xylem and phloem. In human beings, excretory products
in the form of soluble nitrogen compounds are removed by the nephrons
in the kidneys. Plants use a variety of techniques to get rid of waste

SCIENCE CLASS 10 Chapter 7 – Control and Coordination

Chapter 7 of Class 10 teaches about control and coordination which
are the functions of the nervous system and hormones in our bodies. The
responses of the nervous system can be classified as a reflex action,
voluntary action or involuntary action. The nervous system uses
electrical impulses to transmit messages. It gets information from our
sense organs and acts through our muscles. Chemical coordination is seen
in both plants and animals. Hormones produced in one part of an
organism move to another part to achieve the desired effect. A feedback
mechanism regulates the action of the hormones.

SCIENCE CLASS 10 Chapter 8 – How do Organisms Reproduce

Unlike other life processes, reproduction is not essential to
maintain the life of an individual organism. It involves the creation of
a DNA copy and additional cellular apparatus by the cell involved in
the process. Depending on their body design, various organisms use
different modes of reproduction. In fission, many bacteria and protozoa
simply divide into two or more daughter cells. Organisms such as hydra
can regenerate if they are broken into pieces. They can also give out
buds which mature into new individuals. Roots, stems and leaves of some
plants develop into new plants through vegetative propagation. These are
examples of asexual reproduction where new generations are created from
a single individual. Sexual reproduction involves two individuals for
the creation of a new individual. DNA copying mechanisms create
variations which are useful for ensuring the survival of the species.
Modes of sexual reproduction allow for greater variation to be

Reproduction in flowering plants involves the transfer of pollen
grains from the anther to the stigma which is referred to as
pollination. This is followed by fertilisation. Changes in the body at
puberty, such as an increase in breast size in girls and new facial hair
growth in boys, are signs of sexual maturation. The male reproductive
system in human beings consists of testes which produce sperms, vas
deferens, seminal vesicles, prostate gland, urethra and penis. The
female reproductive system in human beings consists of ovaries,
fallopian tubes, uterus and vagina. Sexual reproduction in human beings
involves the introduction of sperm in the vagina of the female.
Fertilisation occurs in the fallopian tube. Contraception to avoid
pregnancy can be achieved by the use of condoms, oral pills, copper -T
and other methods.

SCIENCE CLASS 10 Chapter 9 – Heredity And Evolution

We have seen that reproductive processes give rise to new individuals
that are similar, but subtly different. We have discussed how some
amount of variation is produced even during asexual reproduction. The
Rules for the Inheritance of Traits in human beings relate to the fact
that both the father and the mother contribute practically equal amounts
of genetic material to the child. This means that each trait can be
influenced by both paternal and maternal DNA. Sex can be determined by
different factors in various species. Changes in the non-reproductive
tissues caused by environmental factors are not inheritable. Speciation
may take place when the variation is combined with geographical
isolation. Evolutionary relationships are traced in the classification
of organisms. Tracing common ancestors back in time leads us to the idea
that at some point in time, non-living material must have given rise to

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Evolution can be worked out by the study of not just living species,
but also fossils. Complex organs may have evolved because of the
survival advantage of even the intermediate stages. Organs or features
may be adapted to new functions during the course of evolution.
Evolution cannot be said to progress from lower forms to higher forms.
Rather, evolution seems to have given rise to more complex body designs
even while the simpler body designs continue to flourish. Study of the
evolution of human beings indicates that all of us belong to a single
species that evolved in Africa and spread across the world in stages.

SCIENCE CLASS 10 Chapter 10 – Light Reflection and Refraction

In  NCERT Class 10 Science Chapter 10, we will study the phenomena of
reflection and refraction of light using the straight-line propagation
of light. These basic concepts will help us in the study of some of the
optical phenomena in nature. The chapter also discusses the reflection
of light by spherical mirrors and refraction of light and their
application in real life. Light is a source of energy which generates a
sensation of vision in human beings. Light seems to travel in straight
lines. The different types of a spherical mirror, convex and concave are
taught. The various terms related to spherical mirrors like the centre
of curvature, the radius of curvature, etc, focus, pole, etc are
discussed with ray diagrams. Uses of a spherical mirror are also
discussed in this chapter. Mirror formula gives the relationship between
the object-distance, image-distance, and focal length of a spherical
mirror. The focal length of a spherical mirror is equal to half its
radius of curvature.

Refraction is the bending of a wave when it enters a medium where its
speed is different. The refraction of light when it passes from a fast
medium to a slow medium bends the light rays toward the normal to the
boundary between the two media. The phenomena of refraction can be
understood easily by the concepts of the refractive index and optical
density. The refractive index of a transparent medium is the ratio of
the speed of light in a vacuum to that in the medium. In case of a
rectangular glass slab, the refraction takes place at both the air-glass
interface and glass-air interface. The emergent ray is parallel to the
direction of the incident ray. Lens formula gives the relationship
between the object-distance, image-distance, and the focal length of a
spherical lens. Power of a lens is the reciprocal of its focal length.
The SI unit of power of a lens is dioptre.

SCIENCE CLASS 10 Chapter 11 -The Human Eye and Colorful World

In the previous chapter, we learnt about light and some of its
properties. In this chapter, we will study some of the optical phenomena
in nature. The chapter also discusses the rainbow formation, splitting
of white light and blue colour of the sky. The human eye is one of the
most valuable and sensitive sense organs. It enables us to see the
wonderful world and the colours around us. The ability of the eye to
focus on both near and distant objects, by adjusting its focal length,
is called the accommodation of the eye. The smallest distance, at which
the eye can see objects clearly without strain, is called the near point
of the eye or the least distance of distinct vision. For a young adult
with normal vision, it is about 25cm. The common refractive defects of
vision include myopia, hypermetropia and presbyopia. Myopia,
short-sightedness-the image of distant objects is focused before the
retina is corrected by using a concave lens of suitable power.
Hypermetropia (far-sightedness-the image of nearby objects is focussed
beyond the retina) is corrected by using a convex lens of suitable
power. The eye loses its power of accommodation at old age. The
splitting of white light into its component colours is called
dispersion. Scattering of light causes the blue colour of the sky and
the reddening of the Sun at sunrise and sunset.

SCIENCE CLASS 10 Chapter 12 – Electricity

Electricity has an important place in modern society. It is a
controllable and convenient form of energy for a variety of uses in
homes, schools, hospitals, industries and so on. It is a phenomenon
related to the flow of charge. A stream of electrons moving through a
conductor constitutes an electric current. Conventionally, the direction
of current is taken opposite to the direction of flow of electrons. The
SI unit of electric current is ampere. To set the electrons in motion
in an electric circuit, we use a cell or a battery. A cell generates a
potential difference across its terminals. It is measured in volts (V).
Resistance is a property that resists the flow of electrons in a
conductor. It controls the magnitude of the current. The SI unit of
resistance is Ohm. Ohm’s law: the potential difference across the ends
of a resistor is directly proportional to the current through it,
provided its temperature remains the same. The resistance of a conductor
depends directly on its length, inversely on its areas of
cross-section, and also on the material of the conductor. The equivalent
resistance of several resistors in series is equal to the sum of their
individual resistances. The electrical energy dissipated in a resistor
is given by W=V x I x t. The unit of power is watt (W). One watt of
power is consumed when 1 A of current flows at a potential difference of
1 V. The commercial unit of electrical energy is kilowatt-hour (kWh).
1kW h = 3,6000,000 J = 3.6 x 106 J.

SCIENCE CLASS 10 Chapter 13 – Magnetic Effects of Electric Current

In this chapter you will study magnetic fields and such
electromagnetic effects, along with electromagnets and electric motors
which involve the magnetic effect of electric current, and electric
generators, which involve the electric effect of moving magnets. A
compass needle is a small magnet. Its one end, which points towards the
north, is called a north pole, and the other hand, which points towards
the south, is called a south pole. A magnetic field exists in the region
surrounding a magnet in which the force of the magnet can be detected.
Field lines are used to represent a magnetic field. A field line is a
path along which a hypothetical free north pole would tend to move. The
direction of the magnetic field at a point is given by the direction
that a north pole placed at that point would take. Field lines are shown
closer together where the magnetic field is greater. A metallic wire
carrying an electric current has associated with it a magnetic field.
The field lines about the wire consist of a series of concentric circles
whose direction is given by the right-hand rule. The pattern of the
magnetic field around a conductor due to an electric current flowing
through it depends on the shape of the conductor. The magnetic field of a
solenoid carrying a current is similar to that of a bar magnet. An
electromagnet consists of a core of soft iron wrapped around with a coil
of insulated copper wire. A current-carrying conductor, when placed in a
magnetic field, experiences a force. If the direction of the field and
that of the current are mutually perpendicular to each other, then the
force acting on the conductor will be perpendicular to both and will be
given by Fleming’s left-hand rule. This is the basis of an electric
motor. An electric motor is a device that converts electric energy into
mechanical energy.


The phenomenon of electromagnetic induction is the production of
induced current in a coil placed in a region where the magnetic field
changes with time. The magnetic field may change due to relative motion
between the coil and a magnet placed near to the coil. If the coil is
placed near a current-carrying conductor, the magnetic field may change
either due to a change in the current through the conductor or due to
the relative motion between the coil and conductor, the magnetic field
may change either due to a change in the current through the conductor
or due to the relative motion between the coil and the conductor. The
direction of the induced current is given by Fleming’s right-hand rule. A
generator converts mechanical energy into electrical energy. It works
on the basis of electromagnetic induction. There are 2 types of
generator AC and DC generator. Fuse is the most important safety device,
used for protecting the circuits due to short-circuiting or overloading
of the circuits.

SCIENCE CLASS 10 Chapter 14 – Sources of Energy

Our energy requirements increase with our standard of living. In
order to fulfil our energy requirements, we try to improve the
efficiency of energy usage and also try and exploit new sources of
energy. The chapter discusses different sources of energy and they are
conventional sources of energy, which we keep on using for many years.
It includes fossil fuels, thermal power plants and hydropower plants.
The advantages and disadvantages are also discussed. After those
improvements in the technology for using conventional sources of energy
is also discussed such as Biomass and wind energy. Next, you will study
the topic of alternative or non-conventional energy resources. It
includes solar energy, in which energy is generated through the solar
cell and solar panel. Energy can be generated from the sea such as Tidal
energy, wave energy and ocean thermal energy. Energy can also be
generated from the earth’s crust, known as geothermal energy. Nuclear
energy is energy in the nucleus (core) of an atom. The energy source we
select would depend on factors like the ease and cost of extracting
energy from the source, the efficiency of the technology available for
using that source of energy and the environmental impact of using that
source. Many of the sources ultimately derive their energy from the Sun.
All the topics are explained with the advantages and disadvantages of

SCIENCE CLASS 10 Chapter 15 – Our Environment

This chapter discusses how various components in the environment
interact with each other and how we impact the environment. The various
components of an ecosystem are interdependent. The producers make the
energy from sunlight available to the rest of the ecosystem. There is a
loss of energy as we go from one trophic level to the next, this limits
the number of trophic levels in a food chain. The food-chain is
explained in detail with examples according to nature, such as in the
forest, in grassland and in the pond. Human activities have an impact on
the environment. The use of chemicals like CFCs has endangered the
ozone layer. Since the ozone layer protects against the ultraviolet
radiation from the Sun, this could damage the environment. The waste we
generate may be biodegradable or non-biodegradable. The disposal of the
waste we generate is causing serious environmental problems.

SCIENCE CLASS 10 Chapter 16 – Sustainable Management of Natural Resources

In the previous class, we have learned about some natural resources
like soil, air and water and how various components are cycled over and
over again in nature. In this chapter, we will look at some of our
resources and how we are using them. Our resources like forests,
wildlife, water, coal and petroleum need to be used in a sustainable
manner. We can reduce pressure on the environment by sincerely applying
the maxim of ‘Refuse, Reduce, Reuse, Repurpose and Recycle’ in our
lives. Management of forest resources has to take into account the
interests of various stakeholders. The harnessing of water resources by
building dams has social, economic and environmental implications.
Alternatives to large dams exist. These are locale-specific and may be
developed so as to give local people control over their local resources.
The fossil fuels, coal and petroleum, will ultimately be exhausted.
Owing to this and because their combustion pollutes our environment, we
need to use these resources judiciously.


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