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NCERT Solutions for Class 9 Science Chapter 8

NCERT Solutions for Class 9th: Ch 8 Motion

NCERT Solutions for Class 9 Science Chapter 8 – Motion is defined for movement. If any object is continuously changing its position with time, it is said to be in motion. Examples are, a moving car, a boy running. If any object is not changing its position with time it is said to be in rest. A body may be in rest for one object and in motion for another. Two people sitting in train are in rest with respect to each other. But, they are in motion with some person the train. So, rest or motion is defined for some particular reference point. Here, we are basically concerned about straight line motion. Distance is total path covered by a person in motion. Speed defined as distance travelled by time taken. Displacement is defined as shortest distance between initial and final distance.

Velocity is defined as displacement by time. After that, concept of uniform and Non-uniform motion is discussed. Uniform motion is defined as when same distance is travelled at same time. The acceleration of an object is the change in velocity per unit time. Uniform and non-uniform motions of objects can be shown through graphs. Distance time and velocity time graph has been discussed. The motion of an object moving at uniform acceleration can be described with the help of equation of motion.

v=u+at
S=ut +1/2 at2
v2-u2=2as

Here, v is final velocity, u is initial velocity, a is acceleration, s is displacement, t is time. If an object moves in a circular path with uniform speed, its motion is called uniform circular motion.

NCERT Solutions for Class 9 Science Chapter 7

NCERT Solutions for Class 9th: Ch 7 Diversity in Living Organisms

NCERT Solutions for Class 9 Science Chapter 7 – Diversity in Living Organisms Each organism is different from the other to a lesser or greater extent. We all can consider people around us. They all are having different types nose, different colours of eyes. These differences are among human beings. These differences become more if we move from human beings to monkeys, and increases more if we mover from human beings to fish. The living world is diverse in many ways. This different variety of life around us has evolved on the earth over millions of years. However, we do not have more than a tiny fraction of this time to try and understand all these living organisms, so we cannot look at them one by one.

Instead, we look for similarities among the organisms, which will allow us to put them into different classes and then study different classes or groups as a whole. Different diverse groups can be created based on certain characteristics. Attempts at classifying living things into groups have been made since time immemorial. The characteristics of body design used for classification of plants will be very different from those important for classifying animals. This is because the basic designs are different, based on the need to make their own food (plants), or acquire it (animals). Therefore, these design features (having a skeleton, for example) are to be used to make sub-groups, rather than making broad groups.

NCERT Solutions for Class 9 Science Chapter 6

NCERT Solutions for Class 9th: Ch 6 Tissues

NCERT Solutions for Class 9 Science Chapter 6 – Tissues In unicellular organisms, a single cell performs all basic functions. For example, in Amoeba, a single cell carries out movement, intake of food and gaseous exchange and excretion. But in multi- cellular organisms there are millions of cells. Most of these cells are specialised to carry out specific functions. Each specialised function is taken up by a different group of cells. We can say that, multi-cellular organisms show division of labour. Cells specialising in one function are often grouped together in the body.

A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue. There is difference in animal tissues and plant tissues. Plant tissues are of two main types – meristematic and permanent. Meristematic tissue is the dividing tissue present in the growing regions of the plant. Permanent tissues are derived from meristematic tissue once they lose the ability to divide. They are classified as simple and complex tissues. Parenchyma, collenchyma and sclerenchyma are three types of simple tissues. Xylem and phloem are types of complex tissues. Animal tissues can be epithelial, connective, muscular and nervous tissue. Depending on shape and function, epithelial tissue is classified as squamous, cuboidal, columnar, ciliated and glandular.

NCERT Solutions for Class 9 Science Chapter 5

NCERT Solutions for Class 9th: Ch 5 Fundamental Unit of Life

NCERT Solutions for Class 9 Science Chapter 5 – Fundamental Unit of Life this was in the year 1665 when Robert Hooke made an important observation through a self-designed microscope. He saw that the cork resembled the structure of a honeycomb consisting of many little compartments. Cork is a substance which comes from the bark of a tree. Cell is a Latin word for ‘a little room’. This was an important incident took place history of science. This was the very first time that someone had observed that living things appear to consist of separate units. Cell is the basic building block of all living beings. The shape and size of cells are related to the specific function they perform. Some cells like Amoeba have changing shapes. Each living cell has the capacity to perform certain basic functions that are characteristic of all living forms. These are activities like digestion of food, respiration, transportation etc.

Structure of Cell is discussed in this chapter. Cells are enclosed by a plasma membrane composed of lipids and proteins. The cell membrane is an active part of the cell. It regulates the movement of materials between the ordered interior of the cell and the outer environment. In plant cells, a cell wall composed mainly of cellulose is located outside the cell membrane. The presence of the cell wall enables the cells of plants, fungi and bacteria to exist in hypotonic media without bursting. . The nucleus in eukaryotes is separated from the cytoplasm by double-layered membrane and it directs the life processes of the cell.

Cell organelles are discussed one by one The ER functions both as a passage way for intracellular transport and as a manufacturing surface. The Golgi apparatus consists of stacks of membrane-bound vesicles that function in the storage, modification and packaging of substances manufactured in the cell. Most plant cells have large membranous organelles called plastids, which are of two types – chromoplasts and leucoplasts. Mitochondria are known as the powerhouses of the cell. Energy is generated in this.

NCERT Solutions For Class 9 Science Chapter 4

NCERT Solutions for Class 9th: Ch 4 Structure of Atom

NCERT Solutions For Class 9 Science Chapter 4 – Structure of Atom are the fundamental building blocks of matter. The existence of different kinds of matter is due to different atoms constituting them. In the chapter we are going to discuss the constituents of atoms and how this constitutes are arranged in the atom. Defining atom was the major challenge before the scientists. It was known by 1900 that the atom was indivisible particle but contained at least one sub-atomic particle – the electron identified by J.J. Thomson. Credit for the discovery of electron and proton goes to J.J. Thomson and E.Goldstein, respectively.

The first model of atom was plum pudding model of Thomson. After that, Ruther fold’s idea came into existence. His atomic model was based on alpha-particle scattering experiment done by him. We have to study his experiment and its observation. Rutherford’s model of the atom proposed that a very tiny nucleus is present inside the atom and electrons revolve around this nucleus. The stability of the atom could not be explained by this model. So, more suitable model was to be found.

Neils Bohr’s model of the atom was more successful. He proposed that electrons are distributed in different shells with discrete energy around the nucleus. If the atomic shells are complete, then the atom will be stable and less reactive. J. Chadwick discovered presence of neutrons in the nucleus of an atom. So, the three sub-atomic particles of an atom are: (i) electrons, (ii) protons and (iii) neutrons. Electrons are negatively charged, protons are positively charged and neutrons have no charges. The mass of an electron is about 1/2000 times the mass of hydrogen atom. The mass of a proton and a neutron is taken as one unit each. Shells of an atom are designated as K,L,M,N,… Valency is the combining capacity of an atom. The atomic number of an element is the same as the number of protons in the nucleus of its atom. The mass number of an atom is equal to the number of nucleons in its nucleus. Isotopes are atoms of the same element, which have different mass numbers. Isobars are atoms having the same mass number but different atomic numbers. Elements are defined by the number of protons they possess.

NCERT Solutions For Class 9 Science Chapter 3

NCERT Solutions for Class 9th: Ch 3 Atoms and Molecules

NCERT Solutions For Class 9 Science Chapter 3 – Atoms and Molecules An Indian philosopher Maharishi Kanad, postulated that if we go on dividing matter (padarth), we shall get smaller and smaller particles. Ultimately, a stage will come when we shall come across the smallest particles beyond which further division will not be possible. He named these particles Parmanu. In same era, ancient Greek philosophers – Democritus and Leucippus suggested that if we go on dividing matter, a stage will come when particles obtained cannot be divided further. Democritus called these indivisible particles atoms which means indivisible. These were philosophies.

They were not based on experiments. The chapter starts with laws of chemical compositions – Law of constant proportion, Law of conservation of mass. During a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is known as the Law of Conservation of Mass. In a pure chemical compound, elements are always present in a definite proportion by mass. This is known as the Law of Definite Proportions. Concept of atom is discussed.

An atom is the smallest particle of the element that cannot usually exist independently and retain all its chemical properties. A molecule is the smallest particle of an element or a compound capable of independent existence under ordinary conditions. It shows all the properties of the substance. A chemical formula of a compound shows its constituent elements and the number of atoms of each combining element. Clusters of atoms that act as an ion are called polyatomic ions. They carry a fixed charge on them. The chemical formula of a molecular compound is determined by the valency of each element. In ionic compounds, the charge on each ion is used to determine the chemical formula of the compound. Scientists use the relative atomic mass scale to compare the masses of different atoms of elements.

Mole concept has been dealt. Atoms of carbon-12 isotopes are assigned a relative atomic mass of 12 and the relative masses of all other atoms are obtained by comparison with the mass of a carbon-12 atom. The Avogadro constant 6.022 × 1023 is defined as the number of atoms in exactly 12 g of carbon-12. The mole is the amount of substance that contains the same number of particles (atoms/ ions/ molecules/ formula units etc.) as there are atoms in exactly 12 g of carbon-12. Mass of 1 mole of a substance is called its molar mass.

NCERT Solutions For Class 9 Science Chapter 2

NCERT Solutions for Class 9th: Ch 2 Is Matter Around us pure?

NCERT Solutions For Class 9 Science Chapter 2 – Is Matter Around us pure? So, is there any way to find out whether substances of daily use, like ghee, milk, even water is pure or not? Such ways are discussed in this chapter. In fact, milk itself is not a pure substance. It is a mixture. Mixtures are constituted by more than one kind of pure form of matter. Pure substances can be elements or compounds Different types of mixtures are discussed in this chapter-Solution, suspension and colloidal. A solution is a homogeneous mixture of two or more substances. The major component of a solution is called the solvent, and the minor, the solute. The concentration of a solution is the amount of solute present per unit volume or per unit mass of the solution. Materials that are insoluble in a solvent and have particles that are visible to naked eyes, form a suspension. A suspension is a heterogeneous mixture. Colloids are heterogeneous mixtures in which the particle size is too small to be seen with the naked eye, but is big enough to scatter light. Colloids are useful in industry and daily life.

The particles are called the dispersed phase and the medium in which they are distributed is called the dispersion medium. Properties of solution, colloid and suspension are discussed in detail. Different methods to separate components of mixture are discussed. Some of them are chromatography, distillation, Crystallisation. Physical and chemical changes are discussed. . An element is a form of matter that cannot be broken down by chemical reactions into simpler substances. A compound is a substance composed of two or more different types of elements, chemically combined in a fixed proportion. Properties of a compound are different from its constituent elements, whereas a mixture shows the properties of its constituting elements or compounds.

NCERT Solutions For Class 9 Science Chapter 1

NCERT Solutions for Class 9th: Ch 1 Matter in Our Surroundings

NCERT Solutions For Class 9 Science Chapter 1 – Matter in Our Surroundings Everything in this universe is made up of material which scientists have named “matter”. The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand everything is matter. Early Indian philosophers classified matter in the form of five basic elements – the “Panch Tatva”– air, earth, fire, sky and water. Modern day scientists have evolved two types of classification of matter based on their physical properties and chemical nature, both of them are discussed in this chapter. First physical properties are discussed. Matter is made up of particles. Size of particles are very small. There are spaces between particles. It can be observed through experiments. When solute particels are dissolved in solution. Relative experiments has been discussed. Particles of matter attract each other. All these physical properties are studied with relevant experiments. Different states of matter solid, liquid and gas is discussed with their relative physical properties like intermolecular forces of attraction, shape, size and composition of particles in them. Matter can change their state from solid to liquid, liquid to gas, gas to liquid.

For example, water on heating changes to its gaseous state, steam. On cooling water changes into ice which is the solid state of water. Change in pressure can also change physical state. For example, Increase in pressure, will make particles come together, so, gas can be converted into liquid. Process of evaporation is discussed with concept of latent heat. Latent heat is the heat energy required for change in physical state. In the case of liquids, a small fraction of particles at the surface, having higher kinetic energy, is able to break away from the forces of attraction of other particles and gets converted into vapour. This phenomenon of change of a liquid into vapours at any temperature below its boiling point is called evaporation. Factors on which evaporation and its rate depend are discussed. Heat, wind, humidity are factors. Evaporation increases with increase in temperature, wind speed and decrease with humidity. Evaporation takes place of surface water by taking heat from below. Since, heat is lost, cooling effect can be observed.

NCERT Solutions Class 9 Science

NCERT Solutions for Class 9 Science

Class 9th Science Textbook builds the foundation of Class 9 students. The textbook is divided into three disciplines physics, chemistry and biology not officially but in the question papers. You need to understand the basic concepts of physics and chemistry before trying to solve NCERT questions. Here, we are providing you NCERT Solutions for Class 9 Science that will help you in finding the correct and to the point solution if you ever get stuck in a question. You only need to click on the desired chapter name to get solutions of that chapter.

Class 9 Science NCERT Chapter Wise Solutions

NCERT Solutions for Class 9 Maths Chapter 15

NCERT Solutions for Class 9 Maths Chapter 15 – Probability

NCERT Solutions for Class 9 Maths Chapter 15 Probability helps students in learning basic concepts of probability, its experimental approach in detail. NCERT Solutions for Class 9 Maths, provides answers to all the questions printed in the exercise present at the end of the chapter. These solutions are prepared by our mathematics experts who are highly experienced in the field of education industry. The solutions are genuine and are created after extensive research on each topic. Students can refer to this study material to boost their confidence, and attempt the exam smartly. The concepts are explained with steps, shortcuts to remember formula, tips and tricks to solve the numerical problems wisely and quickly. Average Number of marks from statistics and probability is 10. The solutions to the following exercises have been provided below.

Exercise 15.1 Solutions 10 Question ( 4 short, 3 long, 3 very long)