Physics Exercise Class 9 Chapter 1

[Hedvige Ransonet]

Thefirst 6 chapters were originally prepared in 1997-98, Chapter 7 wasadded in 1999, and Chapter 9 was added in 2004.A typeset version of Chapter 8 (on fault-tolerant quantum computation)is not yet available; nor are the figures for Chapter 7. Additional material isavailable in the form of handwritten notes.

The theory of quantum information and quantum computation. Overview ofclassical information theory, compression of quantum information, transmissionof quantum information through noisy channels, quantum entanglement, quantumcryptography. Overview of classical complexity theory, quantum complexity,efficient quantum algorithms, quantum error-correcting codes, fault-tolerantquantum computation, physical implementations of quantum computation.

Certainly it would be useful to have had a previous course on quantummechanics, though this may not be essential. It would also be useful to knowsomething about (classical) information theory, (classical)coding theory, and (classical) complexity theory, since a central goal ofthe course will be generalize these topics to apply to quantum information.But we will review this material when we get to it, so you don't need to worryif you haven't seen it before. In the discussion of quantum coding, we will usesome rudimentary group theory.

In fact, quantum information -- information storedin the quantum state of a physical system -- has weird properties that contrastsharply with the familiar properties of "classical" information. Anda quantum computer -- a new type of machine that exploits the quantumproperties of information -- could perform certain types of calculations farmore efficiently than any foreseeable classical computer.

In this course, we will study the properties that distinguish quantuminformation from classical information. And we will see how these propertiescan be exploited in the design of quantum algorithms that solve certain problemsfaster than classical algorithms can.

A quantum computer will be much more vulnerable than a conventional digitalcomputer to the effects of noise and of imperfections in the machine.Unavoidable interactions of the device with its surroundings will damage thequantum information that it encodes, a process known as decoherence.Schemes must be developed to overcome this difficulty if quantum computers areever to become practical devices.

In this course, we will study quantum error-correcting codes that can beexploited to protect quantum information from decoherenceand other potential sources of error. And we will see how coding can enable aquantum computer to perform reliably despite the inevitable effects of noise.

NCERT Solutions for Class 11 Physics for all chapters can be accessed here by following the links provided below. The highly experienced subject matter experts have explained each and every minute concept in the best way possible to help students face the exam without fear. Physics is a subject which contains a lot of concepts and numerical problems. For this purpose, a thorough understanding of the concepts is necessary to solve the problems effortlessly. NCERT Solutions is prepared in order to provide the students with authentic information completely based on the latest syllabus prescribed by the CBSE board.

NCERT Solutions Class 11 Physics is an important study material which helps students to master the subject. Physics is a crucial subject from the exam perspective, which is difficult to master as it deals with various properties of nature and matter. It forms a strong base for students who wish to pursue higher levels of education in the field of Science. The solutions are planned out to aid the Class 11 students in achieving good marks in the exam. The expert teachers answer each and every question in an elaborate manner so that students do not miss any concept which is important for the exam. By regular practice using the NCERT Solutions, students will be able to know the right way to approach the questions which would appear in the exam.

In this chapter, we will be studying how things work and the reason behind it. Students will become more aware of the things surrounding them, the origin and the history of Science. They will also come across various aphorisms and their justification using Physics concepts in real life in this chapter. The concepts covered here are gravitational force, electromagnetic force, strong and weak nuclear force. The theories and observations done by various scientists and their conclusion is provided briefly here. You will gain more idea about the factors which are the reasons for the development of Science and Technology in our country. The existence of an electron is explained in this chapter in an elaborate manner to acquaint students with the basic conceptual knowledge.

With the senses like ears, eyes etc., scientists gather information and make observations. A few of them are like figuring out the colour and texture, while others would be complex where measurement is necessary. It is a basic concept in Science without which scientists will not be able to conduct any experiments. Students will learn about the units of physical quantities and the method to be followed to evaluate them. It will also provide a good idea of the errors which would occur while measuring things and significant figures.

Need for measurement: Units of measurement; systems of units; SI units, fundamental and derived

units. Length, mass and time measurements; accuracy and precision of measuring instruments; errors in measurement; significant figures.

Dimensions of physical quantities, dimensional analysis and its applications.

Frame of reference. Motion in a straight line: Position-time graph, speed and velocity. Uniform and non-uniform motion, average speed and instantaneous velocity.

Uniformly accelerated motion, velocity-time and position-time graphs, relations for uniformly accelerated motion (graphical treatment).

Elementary concepts of differentiation and integration for describing motion.

Students will learn about the scalar and vector quantities and their difference. The method of performing algebraic expressions on various scalar quantities are also explained here. Besides, true or false questions based on these concepts and their justification are elaborated under each answer. We will also learn the concept of magnitude of vectors and their co-linearity, magnitude of displacement vector and the various types of displacement of a moving vehicle. It will help us to understand the time taken by a person to cross a river, experience of riding a bicycle in rain and a ball thrown by a cricketer in the ground.

This chapter is very important in mechanics. Problems based on the conservation of momentum are frequently asked in the exam. By going through this chapter, students will become well-versed with the laws of motion and their applications in our daily activities. Various numerical problems based on mechanics are solved clearly in this chapter to boost the exam preparation of students. Having a good knowledge of these concepts, students will be able to pursue well in their higher education levels.

The Work Energy Theorem is an important concept in this chapter. Students are highly recommended to learn this chapter effectively as it is continued in future classes also. The work done by a person and the energy required to do that work is explained briefly with suitable examples to make the students well-versed with the concepts. Problems on determining the energy and power are solved in a step-wise manner based on the mark weightage allotted by the CBSE board. Practising these concepts regularly will make them master the chapter effortlessly.

Scalar product of vectors. Work done by a constant force and a variable force; kinetic energy, work-energy theorem, power.

Notion of potential energy, potential energy of a spring, conservative forces; conservation of mechanical energy (kinetic and potential energies); non-conservative forces; elastic and inelastic collisions in one and two dimensions.

This chapter will help students understand the motion of extended bodies, such as the system of particles. The centre of mass of a system of particles is the main concept in this chapter. The term motion and its usefulness are briefly explained as per the syllabus of the CBSE board. As many concepts are covered under this chapter, students are highly recommended to make use of a perfect study material while answering the exercise questions from the textbook.

Centre of mass of a two-particle system, momentum conservation and centre of mass motion.

Centre of mass of a rigid body; centre of mass of circular ring, disc, rod and sphere.

Vector product of vectors; moment of a force, torque, angular momentum, conservation of angular momentum with some examples.

Equilibrium of rigid bodies, rigid body rotation and equation of rotational motion, comparison of linear and rotational motions; moment of inertia, radius of gyration. Values of M.I. for simple geometrical objects (no derivation). Statement of parallel and perpendicular axes theorems and their applications.

We know that all material objects are attracted towards the Earth. The things which we throw up fall down. Climbing a hill is difficult when compared to going downhill. Gravitation is a very popular concept as most of them which we study in the future are in accordance with this phenomenon. To understand the more complex concepts in this chapter, students should know the difference between gravity and gravitation. The other concepts discussed in this chapter are potential energy difference between two points, acceleration due to gravity and interplanetary motion.

Thermodynamics is a concept of heat and temperature and its conversion to other energy forms. It is one of the main topics which the question paper setters focus on, and most of the questions in the exams can appear from this chapter. In order to attain remarkable grades, it is crucial for students to learn all these concepts effectively. The laws of thermodynamics, specific heat capacity, various thermodynamic processes and the Carnot engine are some of the important concepts covered in this chapter.

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