NCERT Solutions for Class 10th Science

NCERT Solutions for Class 10 Science (Physics, Chemistry and Biology) - Free PDF Download

Science textbook of Class 10th deals with the disciplines such as Physics, Chemistry, Biology
and Environmental Science as integrated. Here, we have provided students NCERT Solutions for Class 10 Science textbook of each chapter so that you'll never face any problem with any question.There is no sharp division made by the NCERT in the textbook. However, as per the examination point of view, we can divide this book into three parts Physics, Chemistry and Biology. Environment Science part is covered in the Biology syllabus. You can select your desired chapter from the list and start your learning.


The whole book is subdivided into four topics namely, Materials, The World of the Living, How Things Work, Natural Phenomena and Natural Resources or in the way of discipline we can state them in Chemistry, Biology, Physics and Environmental Science respectively. As previously stated, Environment Science part is covered in the Biology syllabus. So we have total three subjects in Science subject, Physics, Chemistry and Biology.

NCERT Solutions for Class 10th Science

NCERT Solutions for Class 10 Science will introduce you to the basic concepts of the chapters as the questions are given that check your all round understanding of the chapter. These NCERT Solutions will help you in getting better marks in the examination. You can get ahead of your competitors through these solutions.

The first unit has total five chapters. The first chapter is about the chemical reactions and equations in which we will learn about how to write chemical equations and balance them. Also, we will learn about the various types of chemical reactions. In the second chapter, we will learn about the various types of acids, bases and salts and their reactions with metals and non-metals. The third chapter will take us to the world of metals and non-metals where we will learn about their properties and reactions among them. The fourth chapter is about the carbon and its compounds where we will learn about the properties of carbons and chemical substances containing carbon. In the fifth chapter, we will learn about the classification of elements and their evolution.

The Second unit consists of four chapters that are from sixth to ninth. The sixth chapter is about the various life processes which human need for their survival. In the seventh chapter, we will talk about the parts of the human body which are engaged in control and coordination activities. The eighth chapter deals with reproduction activities in unicellular and multicellular organisms. The ninth chapter, we will learn how the offsprings look alike.

The third unit is How things works which have four chapters. In the tenth chapter, we will learn about light and its phenomena reflection and refraction in a detailed manner. The eleventh chapter is about the human eye and some optical phenomena in nature. The twelfth chapter deals with the electricity in which we will learn electric circuit and resistance. In the thirteenth chapter, magnetic effects of electric current and its applications.

The fourth unit has three chapters in it. The fourteenth chapters talk about the various sources of energy such as conventional and non-conventional sources. The fifteenth chapter is about our environment in which we will learn about the eco-systems, food chains and how human activities contribute in degrading its quality. The last chapter is about the conservation of natural resources.

Chapter 1 - Chemical Reactions and Equations

The chapter first introduces us to the chemical reactions. In previous classes, students were introduced to physical and chemical changes. The chemical changes signify the chemical reactions. The indicators of chemical reactions are explained with some indicators like change in physical state, change in color, change in temperature and evolution of gas. These are explained with some experimental examples. After that writing of chemical equation has been explained. It is symbolic representation of chemical reactions. Also, it has been explained that how such equations can be more informative. For example, balancing a chemical equation will signify that the chemical reactions follow law of conservation of mass. Other information like physical states and conditions required for reactions are mentioned. After that various types of chemical reactions are explained are discussed. The types of chemical reactions are –combination reaction, decomposition reaction, displacement reaction, double decomposition reaction. On basis of energy, exothermic and endothermic reactions are mentioned. Redox reactions are explained which are combination of reduction reaction and oxidation reaction. All types of reactions are explained with suitable example with their respective chemical equation.

Chapter 2 - Acid, Base and Salts

Acid and bases are studied in earlier classes. Acids are defined as substances which are sour in taste and turn blue litmus red. Examples of acids are sour fruits like, Bases are defined as substances which are bitter in taste and turns red litmus blue. Examples of bases are neem, clove, vinegar etc. Here, acids and bases are defined chemically. Acids are substances are which after getting dissolved in water generates Hydrogen ion H+. Hydrogen Ion H+ gets dissolved in water to, form Hydronium Ions H3O+ ions. Examples of acid are Sulphuric Acid, H2SO4, HCl, HNO3, CH3COOH.  Bases are chemically those substances which generate OH- ions in aqueous solutionIf not they are weak acids. Examples are Sodium Hydroxide, NaOH, Potassium Hydroxide KOH etc. After that, various chemical and olfactory indicators are discussed; this indicates the presence of acids or base in the solution. The strength of acids or bases depends upon its capability to generate H+ or OH- ions respectively. Acids are said to be strong if whole of it can be dissociated into H+ ions.  Bases are said to be strong if whole of them get dissociated in water to form OH- ions.  For example, Methyl orange is a chemical indicator. It turns red in acidic solution and yellow in basic solution. Olfactory indicators are indicators which changes odor after coming in contact with acid and base.  For example, smell of clove vanishes when kept in contact with acid. After that acids and bases reactions are discussed with metals, metal oxides and metal carbonates. Reactions between acids and bases are also discussed. They are known as neutralization reactions. Salt is one of the products formed by acid, base reaction. The various types of salts are discussed based on the strength of acid or base. The salts can be neutral, acidic or basic, depends on strength of acid/base used to form the salt. The pH scale Indicates if the solution is acidic, basic our neutral. It is an scale from 0-14. 0 indicates highly acidic solution, 14 indicates highly basic solution. 7 is neutral. So, 0-7 is acidic, 7 is neutral, 7-14 basic solution. Universal indicator is a mixture of several indicators. It shows different colours at different concentrations of H+ ions in the solution. Chloro-alkali process is performed of salt solution. The various chemical substances are formed after reactions, directly or in-directly are used for various process. Some of such chemical salts are Bleaching powder, Washing soda, Baking soda, Plaster of Paris. Their formation and uses are explained in this chapter.

Chapter 3 - Metals and Non-Metals

The chapter starts with physical properties of metals and non-metals. The parameters discussed are some physical properties, like melting and boiling points, physical state at room temperature, ductility, malleability, tensile strength, etc. are also discussed. The metals and non –metals are differentiated on the basis of physical properties. But there are some expectations based on physical properties. For example iodine is non-metal but has lustrous appearance as metal. Mercury is metal but liquid at room temperature. There are more such exceptions. Therefore, classification of metals and non-metals, are based on chemical properties. Chemical reactions of metals with oxygen gas, water, acids and other metal salts are discussed here. The reactions and their condition depends upon the reactivity series. The metals on top of reactivity series are sodium and Potassium. They perform vigorous reactions. Nature of metallic oxides is discussed. Generally Metal oxides are basic in nature. But, some of them like aluminum oxide and zinc oxide can be both acidic and basic and hence known as amphoteric oxides. After that how such reactions takes place is discussed. Ionic bond formation is discussed. Such bond formation can be represented in two forms. Electrons are loosed by metals and gained by non-metals. One get positively charged and another get negatively charged. They get attracted and a strong bond is formed. The first one is electronic configuration. The bond formation is discussed through Bohr model.  Another method is Lewis structure or electron-dot structure. The metals and non-metals are written with their symbol and dots. Number of dots represents number of outermost electron. The properties of ionic bond are discussed which are based on strong ionic bond formation. Extraction of metal is taught. Metals are extracted from minerals, from their ores. Ores are minerals from which extraction of metal is profitable. Impurities are removed and after that processing take place according to reactivity of metals. Higher reactive metals are extracted by electrolysis. Middle reactive metals are first converted into oxides and then reduced to metal. Metals lower in reactivity series such as gold, silver, platinum etc are found in native state and they need not be processed. After this refining of metal is done which is another level of purification. The extracted metals are needed to be protected from corrosion. Lot of money is spent on this. Many methods such as oiling, greasing, electroplating, galavanisation are discussed. Another method is alloying. It is the process of mixing metals with another metals or non-metals. It makes metal corrosion-free and enhances the strength. Steel is an alloy of metal Iron and Non-metal Carbon, used for construction. Other such alloys are stainless steel, brass, bronze, duralumin etc.

Chapter 4 - Carbon and its compounds 

Carbon is versatile element found in many organic and inorganic compounds. The reason of this is its tetravalency and catenation which has been discussed. Carbon form bond by sharing its electrons with other elements. Such bond formations of elements formed by sharing of electron is called covalent- bond formation. Covalent Bond formation is explained for other covalent bond formed compounds such as in oxygen gas, nitrogen gas, and covalent formed compounds. Compound formation is explained in both electron-dot/Lewis-dot structure and electronic configuration. Structure of different carbon compounds is explained. For example, Organic compounds is formed in straight chains, or branched chains or cyclic chains. Organic compounds are also categorised on the basis of saturated and Unsaturated compound.  Saturated compounds are compounds with only single bond. Unsaturated carbon compounds are compounds with double or triple bond. Organic compounds are basically chain of carbon-Hydrogen. Functional groups can be atom or group of atoms attached to the chain of hydrogen-Carbon. Some functional groups are alcohol –OH, carboxylic acid –COOH, Chlorine, -Cl, -Ketone and aldehyde -CHO, Cynide –CN. A system of naming that large number of atoms (nomenclature) is also taught. Some important carbon compounds like ethyl Alcohol used for making alcoholic drinks  and Ethanoic acid used for making vinegar are discussed with their physical and chemical properties. Soaps and detergents are studied with their chemical structure and properties. Their difference is also discussed. The detergents are used for cleaning purpose in hard water.

Chapter 5 - Periodic Classification of Elements

There are 118 known elements found till date. It is better to study each elements in proper way. For this we need to classify them in an order. If categorized in order, we can easily predict some trends in physical and chemical properties of elements. Therefore scientists worked to arrange all elements such that alike elements can be placed in certain rows and column. In the year 1817, Johann Wolfgang Döbereiner showed that when the three elements in a triad were written in the order of increasing atomic masses; the atomic mass of the middle element was roughly the average of the atomic masses of the other two elements. For example, A,B and C form a triad, atomic mass of B is average of atomic masses of A and B. But, this methodology did not worked for every element. Only three triads can be detected. In 1866, John Newlands, tried to arrange elements. Newlands Octave was another method to classify elements. In this every eighth element will show property of first element if placed in order of atomic mass. It was similar to musical notes where first node is similar to eighth. It also failed as it was not able to work for more than 56 elements. Another method was adopted by Dmitri Mendeleev. Mendeleev arranged the elements based on their atomic masses. He observed that when the elements were arranged in increasing order of their atomic masses, there was a periodic recurrence in their physical and chemical properties. Thus, Mendeléev formulated a Periodic Law, which states that ‘the properties of elements are the periodic function of their atomic masses’. Mendeléev’s Periodic Table contains vertical columns called ‘groups’ and horizontal rows called ‘periods’. It was much accurate than previous models. It also had some demerits. Finally, modern periodic came into existence. Atomic number was considered to be criteria for classification. Elements with same group have same number of outermost electron. Elements in same period have same number of outermost shell. A particular increase to decrease in certain pattern can be predicted. Many such trends are studied in this chapter.

Chapter 6 - Life Process

Life processes are various activities performed by living beings for sustaining the life. Such processes are digestive system, respiration system, circulation system etc. All these things are important to leave. The thing is to consume food through digestive system, perform oxidation of food which involves the process of respiration, and transportation of food and water which is done through circulation. This chapter starts with process of nutrition. The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. is nutrition. Other modes of nutrition are autotrophic and heterotrophic nutrition which are discussed in chapter. Autotrophic nutrition is done by plants by photosynthesis. Heterotrophic nutrition is done by animals. Different types of Heterotrophic nutrition are discussed. Parasitic Nutrition, saprophytic Nutrition and Holozonic Nutrition are different types of heterotrophic nutrition. Cellular nutrition is done by unicellular organisms which has been discussed in this chapter. Next topic is nutrition by human beings.  It starts with mouths which include salivary glands, tongue and teeth. The food goes to stomach through oesophagus. The food goes to stomach. Liver secretes greenish yellow liquid called bile juice. Pancreas lies behind the lower portion of stomach. It secretes pancreatic juice which contains many digestive enzymes. All such processes are discussed in this digestive system. Next is respiration. The process of respiration involves: (a) Gaseous exchange i.e. Breathing: Intake of oxygen from the atmosphere and release of CO2. And (b) Cellular respiration: Breakdown of simple food in order to release energy inside the cell. Both are discussed. The human respiration system is discussed with some special attention.  Pharynx ,bronchio lungs, diaphragm are different elements of human respiratory system. Mechanisam of process involves inhale and exhale. Both are explained. Circulation involves the process of transportation of food and other materials from one place to another. The blood is pumped through heart and transported through veins. So, all of them are discussed. Different components of blood are discussed-Red blood cells and White blood cells. Four chambers of heart are discussed.  In plants, We have discussed earlier how plants take in simple compounds such as CO2 and photosynthesise energy stored in their chlorophyll-containing organs, namely leaves. The other kinds of raw materials needed for building plant bodies will also have to be taken up separately. For plants, the soil is the nearest and richest source of raw materials like nitrogen, phosphorus and other minerals. The absorption of these substances therefore occurs through the part in contact with the soil, namely roots.   It has been discussed in details. The biological process involved in the removal of these harmful metabolic wastes from the body is called excretion. Different organisms use varied strategies to do this. It is discussed in details for human beings.  The excretory system of human beings  includes a pair of kidneys, a pair of ureters, an urinary bladder and urethra.

Chapter 7 - Control and Coordination System

Earlier, we had started with a notion we all have, that if we see something moving, it is alive. Some of these movements are in fact the result of growth, as in plants. A seed germinates and grows, and we can see that the seedling moves over the course of a few days, Control and coordination are the functions of the nervous system and hormones in our bodies. The responses of the nervous system can be classified as reflex action, voluntary action or involuntary action.  The nervous system uses electrical impulses to transmit messages.  The nervous system 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.

Chapter 8 - How do organisms reproduce?

Reproduction, unlike other life processes, is not essential to maintain the life of an individual organism. It involves creation of a DNA copy and additional cellular apparatus by the cell involved in the process. Various organisms use different modes of reproduction depending on their body design such as fission, fragmentation, regeneration, budding, spore formation and vegetative propagation. Sexual reproduction involves two individuals for the creation of a new individual. Modes of sexual reproduction allow for greater variation to be generated. Reproduction in flowering plants involves transfer of pollen grains from the anther to the stigma which is referred to as pollination followed by fertilisation. 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.

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. Heredity and evolution deals with the fact – the long-term consequences of the
accumulation of variations. The Rules for the Inheritance of Traits (Mendel’s Contributions) determine the process by which traits and characteristics are reliably inherited. The fact of sex determination in newborn individual is completely solved. 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. Changes in the non-reproductive tissues caused by environmental factors are not inheritable indicates about different traits like Acquired and Inherited. Speciation may take place when variation is combined with geographical isolation. Evolutionary relationships are traced in the classification of organisms. 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.

Chapter 10 - Light: Reflection and Refraction

Light is source of energy which generates sensation of vision in human beings. In this chapter first reflection of light is discussed. Reflection is governed by its laws. The chapter is concerned with laws of reflection. Here we are basically concerned with the spherical mirrors. After that image formation by spherical mirrors are discussed. The different types of spherical mirror, convex and concave are taught. The various terms related with spherical mirrors like centre of curvature, radius of curvature etc, focus, pole etc are discussed with ray diagrams. Uses of spherical mirror has been discussed in chapter. Mirror formula is the way to relate object distance, image distance and focal length of mirror. Magnification is the ratio of size of image by size of object. This is related to ratio of image distance and object distance. Distances are majored from pole of mirror. Sign convention is kept in mind to find relative distances of image and object.

Refraction is the phenomena of bending of light when light travels from one medium to another. Laws of Refraction/Snells law govern refraction. The phenomena of refraction can be understood easily by the concepts of refractive index and optical density. This is better explained by an example of rectangular glass slab. This example is dealt. After that concept of Lens is explained. It is transparent medium bounded by refractive index. Types of Lens –converging and diverging is discussed. Example of converging lens (double convex lens) and diverging (double concave lens).  Image formation and terminology is discussed for both convex and concave lens. Lens formula relates focal length of lens with image distance and object distance. Magnification is related with image and object distance. Sign convention is kept in mind. Power of lens is also discussed. Numerical based on lens formula and mirror formula are to be solved.

Chapter 11 - Human Eye and colorful world

Human eye, its components, are discussed. The process of by which human eye can see objects is discussed.  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 25 cm. Defects of vision is discussed with their corrective measures using suitable ray diagrams. The common refractive defects of vision include myopia, hypermetropia and presbyopia. Myopia (short-sightedness – the image of distant objects is focussed 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 sky and the reddening of the Sun at sunrise and sunset.

Chapter 12 - Electricity

Electricity is required for many thing around us. What is electricity? It is phenomena related to flow of charge. The concept of electric current and electric potential difference (voltage is taught). Flow 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 (Ω).  Ohms Law, which establish relationship between potential difference and current is discussed. 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. Concept of resistance and resistivity is studied. Resistance is property of any conductor to resist flow of current.  The resistance of a conductor depends directly on its length, inversely on its area of cross-section, and also on the material of the conductor. Resistance of conductor having unit length and cross section is defined specific resistance. Series and parallel combination of resistors are discussed. In series current is same and in parallel potential difference is same across resistors.  The electrical energy dissipated in a resistor is given by W = V × I × 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). 1 kWh = 3,600,000 J = 3.6 × 106 J.

Chapter 13 - Magnetic effects of Current

In this chapter relationship between magnetism and electricity is discussed. At first some basics of magnetism is discussed with magnetic field lines. A compass needle is a small magnet. Its one end, which points towards north, is called a north pole, and the other end, which points towards south, is called a south pole. Magnetic Field lines are used to represent a magnetic field. A field line is the 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. The denser magnetic field lines indicate more magnetic field strength. After that, magnetic field due to current carrying conductor is discussed.  A metallic wire carrying an electric current has associated with it a magnetic field whose direction is given by right hand thumb rule. 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. Phenomena related to this are explained.  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. Working and construction of electric motor is discussed. Electricity generation through magnet is discussed.  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 a relative motion between the coil and a magnet placed near to the coil. If the coil is placed near to 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 direction of the induced current is given by the Fleming’s right-hand rule. A generator converts mechanical energy into electrical energy. It works on the basis of electromagnetic induction. Two types of generators are discussed. DC generator generates direct current as a cell. AC generators generates Alternating Current whose direction keep on changing after a time period.
 Domestic circuiting is discussed. In our houses we receive AC electric power of 220 V with a frequency of 50 Hz.  The different aspects is discussed. The concept of live wire, neutral wire and earth wire is discussed. 220V is maintained between live wire which is insulated red and neutral wire which is insulated black. Earth wire, insulated green which provide, passage for leakage of current.

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 is all about different sources of energy. Three types of sources of energy are discussed. The first one is conventional sources of energy. These are sources of energy we keep on using from long years. It include fossil fuels, thermal power plant and hydroelectric power plant. These are discussed with advantages and disadvantages.  After that, energy sources conventionally used, but improvised due to technology has been discussed. For example, cow dung used initially had low calorific value, and combustion of it causes lot of pollution.  But, with help of technology, it can converted into Bio-gas, which is an efficient and pollution free fuel. Similarly, with the help of technology, wind energy can be harnessed by placing many wind mills in a large field creating a wind farm.  Charcoal obtained from wood is better fuel than wood. All these things are discussed. The third category is Non-conventional sources of energy.  In this category, we have energy sources like solar energy, in which energy is generated through solar cell and solar panel,  or  by solar cooker.  Energy from ocean can be generated through waves, tides or through temperature difference between upper and lower level of ocean. Energy can also be obtained from earth crust, known as geo-thermal energy.  Nuclear energy can generated by controlled Nuclear fission reactions. Nuclear fusion reactions generate more energy than fission but are difficult to control. All such sources of energy are discussed with their advantages and disadvantages.

Chapter 15 - Our 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. This concept of food chain and food web is discussed with concept of Biological magnification. It is the process of accumulation of pesticides or other harmful chemicals. Impact of human activities are discussed in this chapter.  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 different types of waste materials are discussed. The waste we generate may be biodegradable or non-biodegradable. The disposal of the waste we generate is causing serious environmental problems. So, a proper waste management system is required.

Chapter 16 - Sustainable Management of Resources

In Class IX, We have been taught 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 shall look at some of our resources and how we are using them.  The chapter introduces us with concern regarding improper use of natural resources. With example of Ganga Action Plan, it has been taught how qualitative and quantitative analysis helps in understanding need of management of natural resources.  Maybe we should also think about how we ought to be using our resources so as to sustain the resources and conserve our environment.  The method of 3R is discussed. We shall be looking at our natural resources like forests, wild-life, water, coal and petroleum and see what are the issues at stake in deciding how these resources are to be managed for sustainable development. Various methods has been discussed such the resources should be used such that natural resources should reach to every section. Also, environmental impact should be considered. Also, limited stock of such resources should be considered.

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