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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.

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 clothes.

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 material.

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 generated.

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 life.

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 it.

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.


Std 10 Science Imp. For Board Examination May 2021 For Gujarati Medium Student
By Bharad Schools

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