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NCERT Solutions for Class 9 Science

NCERT Solutions for Class 9 Science

Edited By Irshad Anwar | Updated on May 20, 2024 06:35 PM IST

NCERT Solutions Class 9 Science - Chapter wise PDF Download (2024–25)

NCERT Solutions for Class 9 Science, updated for the 2024–25 session, are available here. Interest in science in the early stages is a very important factor in deciding career paths in your higher education, especially if you are in CBSE Class 9. In this article, you will find Class 9 Science NCERT Solutions for all chapters explained through a logical approach, making it easy for you to learn science. On a fundamental level, NCERT Science Class 9th is very interesting, but if you do not take an interest, you will be stuck and won't be able to understand the complicated concepts. You could take the help of the NCERT Solutions for Class 9 Science to get the answers. In NCERT Class 9 science Solutions, you will learn about the answers to all the questions given in NCERT books. So, if you want to get high marks in your final exams, these NCERT solutions for class 9 for all chapters will help you do so.

Class 9 Science NCERT Solutions contain solved questions asked in your NCERT Textbook. Students can take advantage of the Class 9 Science Solution. The NCERT science textbook for class 9 is crucial as it teaches the basic chapters to lay a strong foundation for the higher classes like 10th, 11th, and 12th. NCERT 9th Class science textbook will introduce you to four subjects samajik vigyan class 9 physics, chemistry, biology, and environmental science. Natural resources, the laws of motion, force, gravity, sound, atoms, molecules, tissues, and cells are some topics taught in Class 9 Science. Go through the class 9 science question answers provided here.

If you are very curious to know the reason behind everything, and are trying to find the answer to some curious questions like why our body cannot make food from carbon dioxide, water, and minerals like plants do, learning science will be fun for you. Knowing answers to the questions asked in the NCERT textbook is important to scoring well. You could take the help of the NCERT Solutions for Class 9 Science to get the answers. Scoring very good marks can now be a reality with the help of the CBSE NCERT Solutions of Class 9 Science. NCERT solutions, therefore, would be good tools to aid this interest of yours.

Also Read: NCERT Class 9 Science: Chapter-wise Important Formulas, Diagrams, And Points

NCERT Solutions for Class 9th Science Chapter Wise

Chapter-wise NCERT Solutions for Class 9 Science are available in PDF format, offering comprehensive guidance and explanations for all topics. These Class 9 Science Solutions are carefully curated to help students understand complex problems easily and excel in their NCERT Science Class 9 exams. By utilising these PDFs, students can enhance their knowledge, boost problem-solving skills, and achieve academic success in Class 9 Science.

In the NCERT Class 9 Science Textbook for 2023–24, three chapters have been removed out of a total of fifteen chapters to accommodate the updated educational curriculum. But we are providing you Class 9 Science Solutions for all 15 chapters in case you want to brush up your fundamentals for other exams.

NCERT Class 9 Science Solutions: Chapters Brief and Important Topics

Chapter 1: Matter in Our Surroundings

The NCERT Science Class 9 Textbook begins with the chapter "Matter in Our Surroundings," where students learn about the fundamental nature of matter. Everything around us is composed of matter, which occupies space and has mass. Modern scientists classify matter based on physical properties and chemical nature. In NCERT Solutions for Class 9 Science Chapter 1, students delve into the physical properties of matter, exploring the small size and continuous movement of its particles. Matter exists in three states: solids, liquids, and gases, which are a result of variations in particle characteristics. The chapter explains the interconvertibility of these states through changes in temperature and pressure. Evapouration, a surface phenomenon, occurs when a liquid changes into vapour below its boiling point, and its rate depends on the surface area, temperature, humidity, and wind speed. Evaporation also causes cooling. We have explained Class 9 Science Solutions for all the questions asked in the exercise.

Topics Covered in Class 9 Science Chapter 1 Matter in Our Surrounding:

  1. Matter in Our Surroundings
  2. Physical Nature of Matter
  3. Characteristics of Particles of Matter
  4. States of Matter
  5. Can Matter Change its State?
  6. Evaporation

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Chapter 2: Is Matter Around Us Pure

This chapter of NCERT Class 9 Science Solutions is an extension of the basic concept "Mixture" studied in lower classes. It covers topics such as pure substances, various types of solutions (homogeneous and heterogeneous), properties of solutions, mixtures, suspensions, and colloids present in our surroundings. Additionally, Methods of separation crystallisation and evaporation are explored to separate mixtures into pure substances using appropriate techniques. The NCERT Solutions of Class 9 Science in this chapter also include solved numerical problems for better understanding and practice.

Topics Covered in Class 9 Science Chapter 2 Is Matter Around Us Pure:

This chapter of NCERT Science Class 9 covers various aspects of mixtures and their types, including solutions, suspensions, and colloidal solutions. It also discusses separation methods for different mixtures, like obtaining coloured components from ink, separating cream from milk, and separating immiscible and miscible liquids. Furthermore, NCERT Solutions for Class 9 Science Chapter 2 explores physical and chemical changes and types of pure substances like elements and compounds.

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Chapter 3: Atoms and Molecules

In Class 9 Science, the chapter on "Atoms and Molecules" introduces students to molecules, which are electrically neutral groups formed by chemical bonds between two or more atoms. The chapter covers various types of molecules, including molecules of elements and compounds. Students also learn about fundamental concepts such as the law of mass and energy conservation, the law of constant proportion, and Dalton's atomic theory.

CBSE NCERT solutions for Class 9th Science provide in-depth learning on how to write the chemical formula of a molecular compound, understand the mole concept, and calculate the molecular mass of compounds. Additionally, students explore polyatomic ions, which are clusters of atoms that act as ions. NCERT Solutions for Class 9 Science Chapter 3 help students grasp complex concepts, enhance problem-solving skills, and excel in their academic journey.

Topics Covered in Class 9 Science Chapter 3 Atoms and Molecules:

In this chapter, students learn about the Laws of Chemical Combination, including the Law of Conservation of Mass and the Law of Constant Proportions. They explore atoms and their modern symbols for different elements, as well as atomic mass and the existence of atoms. The concept of molecules is introduced, covering molecules of elements and compounds, and the definition of ions. Students also understand how to write chemical formulae, and formulae of simple compounds, and delve into molecular mass and the mole concept, including calculations and formula unit mass.

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Chapter 4: Structure of The Atoms

In the previous chapter, you Studied molecules, which are groups of atoms. Now, you will delve into atoms and their structure. An atom is the smallest, indivisible component of an element. It consists of three sub-atomic particles: protons (positively charged), electrons (negatively charged), and neutrons (electrically neutral). CBSE NCERT solutions for Class 9 Science Chapter 4 also introduce different models of an atom proposed by various scientists. By studying this chapter, you will gain a deeper understanding of the fundamental building blocks of matter and their intricate structure.

Topics Covered in Class 9 Science Chapter 4 Structure of The Atom:

In this chapter, you will explore charged particles in matter and the structure of an atom. Three significant models proposed by scientists—Thomson's, Rutherford's, and Bohr's—will be studied. You'll learn about neutrons, electron distribution in different orbits (shells), valency, atomic number, and mass number. Also, the concept of isotopes and isobars will be covered, enhancing your understanding of atomic structure and characteristics.

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Chapter 5: The Fundamental Unit of Life

In this Biology chapter, students will study the significance of cells as the fundamental unit of life. The chapter explores the structure and functions of cells, including their membranes, cell walls, nucleus, cytoplasm, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, plastids, vacuoles, and cell division. Additionally, students will learn about the impact of hypotonic, hypertonic, and isotonic solutions on cells. The focus of the chapter is on understanding the structural organisation of cells, both in plant and animal cells, highlighting their crucial role in the organisation of living organisms.

Topics Covered in Class 9 Science Chapter 5 The Fundamental Unit of Life:

This chapter focuses on the composition of living organisms and the structural organisation of cells. Students will learn about the plasma membrane, cell wall, nucleus, cytoplasm, and various cell organelles, including endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, plastids, and vacuoles. Understanding these components is crucial in comprehending the functional aspects of cells and living organisms. Go through the NCERT Solutions for Class 9 Science, Chapter 5.

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Chapter 6: Tissues

In the previous chapter, you have already learned that in unicellular organisms, all functions are performed by single cells, but in multicellular organisms, cells are specialised to carry out specific functions. Cells that specialise in one function are grouped together, and this cluster of cells is called a tissue. This cluster of cells is arranged and designed so as to give the highest possible efficiency of function. The tissue is a group of cells similar in structure and function. Plant cells and animal cells are different from each other. Plant tissues are of two main types: meristematic and permanent, and animal tissues can be epithelial, connective, muscular, and nervous. Here, you will study different types of tissues, such as gourd cells, stem cells, etc. If you are having trouble solving exercise questions, go through the NCERT Solutions for Class 9 Science Chapter 6.

Topics Covered in Class 9 Science Chapter 6 The Tissues:

In this chapter, students explore the diverse tissues found in plants and animals. They will learn about meristematic tissue and permanent tissue in plants, including simple and complex permanent tissue. Also, the chapter covers animal tissues, such as epithelial tissue, connective tissue, muscular tissue, and nervous tissue. Understanding these different tissue types will provide insight into the structural and functional aspects of both plants and animals.

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Chapter 7: Diversity in Living Organisms

NCERT Solutions of Class 9 Science: When we see our surroundings, each organism is different from others to a lesser or greater extent. Aristotle was the first person to develop a classification of animals on the basis of living, whether on earth, in water, or in air. In this chapter, you will study that all living organisms are divided on the above bases into five kingdoms, namely Monera, Protista, Fungi, Plantae, and Animalia. Basically, the classification of life forms is related to their evolution. In the NCERT solutions for class 9 science chapter 7, you will also learn about the systematic naming of all living organisms.

Topics Covered in Class 9 Science Chapter 7:

This chapter explores the basis of classification and its relationship with evolution. Students will understand the hierarchy of classification groups, which includes Monera, Protista, Fungi, Plantae, and Animalia. Under Plantae, different subgroups like Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms are covered. Similarly, under Animalia, various subgroups such as Porifera, Coelenterata (cnidaria), Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata, and Vertebrata are explored, including subdivisions like Cyclostomata, Pisces, Amphibia, Reptilia, Aves, and Mammalia. The chapter also covers nomenclature, providing students with a comprehensive understanding of the classification of living organisms.

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Chapter 8: Motion

In our surroundings, we see some objects at rest and some in motion. We say an object is in motion when its position changes with time. Flying birds, swimming fish, and moving cars are some examples of motion. Atoms, molecules, planets, stars, and galaxies are all in motion. It can be described in terms of the distance moved or the displacement. In the Class 9 Science NCERT Solutions of this chapter, you will study displacement, different types of motion, uniform motion, non-uniform motion, circular motion, speed, velocity, acceleration, etc. The motion of an object could be uniform or non-uniform, depending on whether its velocity is constant or changing.

Topics Covered in Class 9 Science Chapter 8 Motion:

In this chapter on motion, students will learn about different aspects of objects moving along a straight line. Topics covered include uniform and nonuniform motion, measuring the rate of motion, speed with direction, rate of change of velocity, and graphical representation of motion using distance-time graphs and velocity-time graphs. Equations of motion will be explored through graphical methods, providing relations between velocity and time, and position and velocity. Additionally, uniform circular motion will be discussed, providing a comprehensive understanding of various aspects of motion in physics.

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Chapter 9: Force and Laws of Motion

In the previous chapter, you have already learned about different types of motion. Now the question is: what causes the motion? Why does the speed of an object change with time? Do all motions require a cause? what is the nature of this cause? In the solutions of NCERT for class 9 science of this chapter, you will get the answers to all these questions. In this chapter, you will study three laws of motion that are given by Newton (Newton's law of motion), Galileo's concept momentum, rate of change of momentum, the net force on a body, etc. IN the CBSE NCERT solutions of class 9 science, you will learn the applications of Newton's law of motion.

Topics Covered in Class 9 Science Chapter 9 Force and Laws of Motion:

In this chapter of physics, "Laws of Motion," students will explore the concepts of balanced and unbalanced forces and their effects on objects. The first law of motion, which deals with inertia, and the concept of mass are covered. The second law of motion, explaining the relationship between force, mass, and acceleration, is discussed. Additionally, the third law of motion, illustrating the principle of action and reaction, will be explored. Finally, students will learn about the conservation of momentum and its significance in understanding the motion of objects. This chapter provides a solid foundation in understanding the fundamental laws governing motion in the field of physics.

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Chapter 10: Gravitation

In the previous chapter, you have already learned about the motion of objects and force on the object as the cause of motion. You know that force is needed to change the speed or direction of motion of an object. You must have observed that an object dropped from a height falls towards the earth. So, there must be a force exerted by the earth on the object that attracts it toward it. This force is called the gravitational force. Any two masses placed at a certain distance will experience gravitational force, but it is a weak force unless large masses are involved. A gravitational force is always an attractive force between two masses. In the NCERT Class 9 Science Solutions, you will learn more about the gravitational force, and how to calculate it. Here, you will learn that the force of gravity decreases with altitude. It also varies on the surface of the earth, decreasing from the poles to the equator.

Topics Covered in Class 10 Science Chapter 10 Gravitation:

In this chapter on "Gravitation," students will learn about the Universal Law of Gravitation and its significance in understanding the force of gravity acting universally between all objects. The concept of free fall and the calculation of the value of "g" are covered, along with the motion of objects under the influence of the Earth's gravitational force. The difference between mass and weight, including the weight of an object on the Moon, is explained. Students will also explore thrust and pressure, with a focus on pressure in fluids and the concept of buoyancy, explaining why objects float or sink in water. Archimedes' Principle and relative density are discussed, providing a comprehensive understanding of gravitation and its practical applications.

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Chapter 11: Work and Energy

We need the energy to perform any activity like playing, singing, reading, writing, thinking, jumping, cycling or running. All living beings get this energy from food. Machines need fuel as energy to perform any activity. Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force. In this chapter, you will learn the concept of work and energy, the relation between work and energy, and different forms of energy (potential and kinetic energy). In the solutions to NCERT for class 9 science, you will learn some applications of work and energy. The unit of work is joule: 1 joule = 1-newton × 1 metre.

Topics Covered in Class 10 Science Chapter 11 Work and Energy:

In this chapter on "Work and Energy," students will Study the scientific conception of work and its connection to a constant force. The concept of energy is introduced, including various forms of energy. The potential energy of an object at a certain height and the interconvertibility of energy forms are discussed. The chapter also covers the Law of Conservation of Energy, emphasising how energy cannot be created or destroyed but can be converted from one form to another. Additionally, the rate of doing work and the commercial unit of energy will be explored, providing a deeper understanding of the relationship between work and energy in various contexts. For more detail, go through the Class 9 Science NCERT Solutions.

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Chapter 12: Sound

We hear sounds from various sources like humans, birds, bells, machines, vehicles, televisions, radios, mobiles, etc. In the previous chapter, you have already learned about mechanical energy. Sound is another form of energy, like mechanical energy, light energy, which produces a sensation of hearing in our ears. Sound is produced due to the vibration of different objects. In the NCERT Class 9 Science Solutions of this chapter, you will learn that the energy of the sound travels and not the particles of the medium for the propagation of the sound. It will cover sound production, propagation of sound, properties, and characteristics of the sound wave, speed of sound in different mediums, reflection of the sound wave, multiple reflections of the sound wave, applications of multiple reflections, reverberation, and application of ultrasound.

Topics Covered in Class 10 Science Chapter 12 Sound:

In this chapter on "Sound," students will learn about the production and propagation of sound. Sound requires a medium to travel and is propagated as longitudinal waves. The characteristics of a sound wave will be explored. Reflection of sound and its effects, such as echo and reverberation, will be covered, along with the uses of multiple reflections of sound. The range of human hearing will be discussed, and applications of ultrasound, including the use of sonar, will be explored. This chapter provides insights into the fascinating world of sound and its various applications in real-life scenarios.

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Chapter 13: Why Do We Fall ill?

In chapters 5 and 6 of Class 9 Science, you have learned that cells are a fundamental unit of all organisms, and specialised cells perform a specific function. All these activities are interconnected. Food is necessary for the proper functioning of cells and tissues. Anything that prevents the proper functioning of cells and tissues will lead to a lack of proper activity in the body. In the NCERT solutions for class 9 science of this chapter, you will learn about different types of diseases, and the causes of diseases like infectious and which are non-infectious. Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents. Go through the NCERT Solutions for Class 9 Science Chapter 13 for more details.

Topics Covered in Class 10 Science Chapter 13 Why Do We Fall ill:

In this chapter on "Why Do We Fall ill" students will learn about the significance of health and how it differs from being disease-free. Both personal and community issues play a crucial role in maintaining good health. The chapter explores the causes of diseases, differentiating between acute and chronic diseases, and how chronic diseases can impact overall health. The focus is on understanding infectious diseases, including their agents, means of spread, and organ-specific and tissue-specific manifestations. Principles of treatment and prevention will be discussed, providing students with valuable insights into maintaining good health and preventing infectious diseases in both personal and community settings.

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Chapter 14: Natural Resources

The land, water, air and energy from the sun are the most important natural resources that we have. Here, you will learn about the importance of natural resources and why we need to conserve them. Air, wind, rain, air pollution, water pollution, minerals in the soil, bio-geochemical cycles, the water cycle, nitrogen cycle, carbon cycle, greenhouse effect, oxygen cycle, ozone layer and depletion of the ozone layer are the important topics that are covered in the solutions of NCERT for class 9 science of this chapter. Also, you will learn that the ozone layer is a very important factor in protecting us from harmful ultraviolet rays that are coming from the sun and how chlorofluorocarbons (CFC) and other air pollutants are depleting the ozone layer. Find more details in NCERT Solutions for Class 9 Science, Chapter 14.

Topics Covered in Class 10 Science Chapter 14 Natural Resources:

In this chapter, students will explore the vital role of air and its composition in climate control, wind movement, and precipitation. The chapter also covers air pollution and its impact. Additionally, students will learn about water as a wonder liquid, water pollution, mineral-rich soil, and the significance of biogeochemical cycles, including the water, nitrogen, carbon, and oxygen cycles. Lastly, the importance of the ozone layer in safeguarding the Earth is discussed.

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Chapter 15: Improvement in Food Resources

As you know, India is a very populous country, and we are still growing. As the population is growing, we need more food. As India is already intensively cultivated, there is no scope for increasing the area of cultivation. Therefore, the only way to increase our production is through the efficiency of crop production and livestock. With the green revolution, we have increased our food production. In the solutions of NCERT for class 9 science of this chapter, you will study the improvements that are required in our food resources. In this chapter, you will also study different types of cultivation of crops for food purposes, like horticulture, pisciculture, etc. Find answers to all your queries from exercise in NCERT Solutions for Class 9 Science Chapter 15.

Topics Covered in Class 10 Science Chapter 15 Improvement in Food Resources:

This chapter covers techniques to enhance crop yields, including crop variety improvement, effective crop production and protection management. Additionally, it explores various aspects of animal husbandry, such as cattle farming, poultry farming, and fish production, including marine and inland fisheries.

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Key Features of NCERT 9th Class Science Solutions

Comprehensive Coverage of Exercise Problems: The NCERT Class 9 Science Book Solutions cover all the exercise problems present in the Class 9 Science textbook. This extensive coverage ensures that students have access to step-by-step solutions for each exercise, enabling them to practice and reinforce their understanding of various science concepts.

Additional Questions, Exemplar Problems, and Important Questions: In addition to the exercise problems, the Class 9 Science Book Solutions include extra questions, exemplar problems, and important questions from previous year's question papers and sample papers. These additional resources serve as valuable supplements, offering students opportunities to explore a wider range of questions and gain exposure to different types of problems.

Solutions in PDF Format for Easy Access: The CBSE Class 9 Science NCERT Solutions are available for download in PDF format. This format ensures easy access to the solutions on various devices, including computers, tablets, and smartphones. Students can conveniently store and review the solutions offline, enabling them to study even without an internet connection.

Inclusion of Diagrams for Visual Representation: The NCERT Class 9 Science Book Solutions include diagrams that complement the textual explanations. These visual representations help students visualise complex concepts and processes, making it easier for them to understand the subject matter.

NCERT Solutions: Class-wise

Tips To Prepare For CBSE Class 9 Science

  • You shouldn't refer to too many resources but instead, stick to the syllabus provided by NCERT.
  • You shouldn't be mugging up the concepts. A better way is to try to understand the concept clearly and relate it to other concepts. Solutions of NCERT for class 9 science will help you to clear your fundamentals
  • You should read and understand the portion that is taught on that day; otherwise, you may find difficulties in understanding the next concepts related to the topic
  • Prepare some short notes at the time of reading the chapter, it will give you a better understanding of the concepts. You can also use these brief notes for quick revision before the exam
  • For the physics part, you should try the NCERT exercise questions. If you are unable to solve on your own, you can take help from these CBSE NCERT solutions for class 9 science, which are provided here.

NCERT Books and NCERT Syllabus:

Frequently Asked Question (FAQs)

1. How many chapters are there in the NCERT Solutions for Class 9 Science?

The NCERT Solutions for Class 9 Science contain a total of 15 chapters.

2. Is the NCERT Solutions for Class 9 Science sufficient for the exam preparation?

Yes, the NCERT Solutions for Class 9 Science are sufficient for exam preparation as they cover all the required concepts and topics in a comprehensive manner. However, additional practice and revision may further improve performance.

3. Are NCERT Solutions for Class 9 Science available in PDF format?

Yes, NCERT Solutions for Class 9 Science are available in PDF format, making it convenient for students to download and access them offline.

4. Can I use NCERT Solutions for Class 9 Science for competitive exams?

NCERT Solutions for Class 9 Science provide a strong conceptual understanding, which can be beneficial for various competitive exams like JEE, NEET and many more.

5. What is NCERT Solutions for Class 9?

NCERT Solutions for Class 9 are comprehensive and detailed answers to the questions and exercises given in the NCERT textbooks for Class 9.


Get answers from students and experts

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg


An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)


Option 2)

\; K\;

Option 3)


Option 4)


In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)


Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)


Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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