# NCERT Exemplar Class 11 Physics Solutions

Share**NCERT Exemplar Class 11 Physics **textbook is meant for both exam preparation and a better understanding of core concepts of Physics. Although NCERT main coursebook is recommended for exam preparation, its counterpart Class 11 Physics Exemplar does the same job while allowing you to understand the concepts in a much easier way. With the help of chapter-wise Class 11 Physics Exemplar Solutions, you will end up solving all the extra questions that are important from the exam perspective.

Selecting the right reference book becomes crucial after you have completed the NCERT main coursebook. The best part is that NCERT Exemplar textbook plays the combined role of reference as well as coursebook. National Council of Educational Research and Training has published this textbook for self-assessment and help you enhance your preparation level.

**NCERT Exemplar Solutions for Class 11 Physics (Chapter-wise)**

- NCERT Solutions for Class 11 Maths
- NCERT Exemplar Class 11 Maths
- NCERT Solutions for Class 11 Physics
- NCERT Solutions for Class 11 Physics Part II
- NCERT Exemplar Class 11 Physics Solutions
- NCERT Solutions for Class 11 Chemistry
- NCERT Solutions for Class 11 Chemistry Part II
- Chemistry - Exemplar
- NCERT Solutions for Class 11 Biology
- NCERT Solutions for Class 11 English Hornbill
- NCERT Exemplar for Class 11 Biology Solutions
- NCERT Solutions for Class 11 English Snapshot
- NCERT Solutions for Class 11 English Woven Words

**Chapter 2: Units and Measurements**

Chapter-2 “Units and Measurements” is based on the measurement of physical quantities. Length, mass, time, electric current, etc. are some of the most common physical quantities that we mention in our day-to-day life. All these physical quantities have their fundamental units.

Next, we will discuss how these physical quantities can be derived. Both fundamental and derived units when combined, represent a system of units. The International System of Units (SI) is the commonly used method for representing the physical quantities. Further, you will study general rules and guidelines for using notations for physical quantities.

Accuracy and precision of measuring instruments are taken into account when performing experiments. Coming to an end, the topic of dimensional analysis will come to play for you to deduce relations among the physical quantities.

**List of Topics in Chapter-2 “Units and Measurements”**

- Introduction
- The international system of units
- Measurement of length
- Measurement of mass
- Measurement of time
- Accuracy, precision of instruments and errors in measurement
- Significant figures
- Dimensions of physical quantities
- Dimensional formulae and dimensional equations
- Dimensional analysis and its applications

Chapter 3: Motion in a Straight Line

Chapter 3: Motion in a Straight Line

You must be familiar with the concept of “Motion in a Straight Line” as you have already read about it in your previous classes. Let us recall that an object is said to be in motion when it has changed its position with respect to time.

Next, in this chapter, you will revisit important definitions of Physics such as path length, displacement, average velocity, average speed, etc. In addition to these, you will come across some more terminologies such as instantaneous velocity, instantaneous acceleration and average acceleration.

Recall the velocity-time graph in which the area covered by an object between t1 and t2 is equal to the displacement of the object. Finally, you will study three equations of motion for objects in uniformly accelerated rectilinear motion. The set of these three equations is also called kinematic equations of motion.

**List of Topics in Chapter-3 “Motion in a Straight Line”**

- Introduction
- Position, path length and displacement
- Average velocity and average speed
- Instantaneous velocity and speed
- Acceleration
- Kinematic equations for uniformly accelerated motion
- Relative velocity

Chapter 4: Motion in a Plane

Chapter 4: Motion in a Plane

The opening topic of Chapter-4 “Motion in a Plane” lists out the differences between scalar and vector quantities. Know how vector addition is both commutative and associative. A zero vector, on the other hand, is characterized by having zero magnitudes.

Further, you will study about the resolution of vectors and representation of its components along the X and Y axes. Learn about the addition of vectors through the analytical method. Projectile motion is the most important topic of this chapter as it will help you find the position and velocity of the projectile of an object at a particular instant of time.

Besides, you will also learn to obtain the path of a projectile, maximum height, total time taken and the horizontal distance travelled by a projectile using respective equations. Towards the end of Chapter-4 of NCERT Class 11 Exemplar Physics, learn to calculate the angular speed and time period of revolution of the object in a circular path.

**List of Topics in Chapter-4 “Motion in a Plane”**

- Introduction
- Scalars and Vectors
- Multiplication of Vectors by Real Numbers
- Addition and Subtraction of Vectors- Graphical Method
- Resolution of Vectors
- Vector Addition- Analytical Method
- Motion in a Plane
- Motion in a Plane with Constant Acceleration
- Relative Velocity in Two Dimensions
- Projectile Motion
- Uniform Circular Motion

**Chapter 5: Laws of Motion**

NCERT Exemplar Class 11 Physics Chapter-5 begins with the discussion about Aristotle’s view of force, which was proved invalid. According to him, it is necessary to exert a force on a body to keep it in uniform motion. Next,

Galileo came up with his observation on the motion of bodies on inclined planes and arrived at the law of inertia. According to Newton’s first law, an object continues to stay in a state of rest or motion, unless an external force is applied to it. Before you jump into Newton’s second and third laws of motion, you need to understand the concepts of momentum and impulse, respectively.

Another familiar topic in this chapter is “Law of Conservation of Momentum” that utilizes the second and third law of motion. The last topic discusses the concept of frictional force and how it is independent of the area of the contact.

**List of Topics in Chapter-5 “Laws of Motion”**

- Introduction
- Aristotle’s Fallacy
- The Law of Inertia
- Newton’s First Law of Motion
- Newton’s Second Law of Motion
- Newton’s Third Law of Motion
- Conservation of Momentum
- Equilibrium of a Particle
- Common Forces in Mechanics
- Circular Motion
- Solving Problems in Mechanics

**Chapter 6: Work, Energy, and Power**

The sixth chapter of NCERT Class 11 Exemplar “Work, Energy, and Power” begins with the work-energy theorem. It is defined as the change in kinetic energy of a body that is equivalent to the work done by the net force on the body. Next, you will study two conditions under which a force is said to be conservative.

As you dig deeper into this chapter, you will study the principle of conservation of mechanical energy and equations for gravitational potential energy and elastic potential energy. Towards the end, you will get to know the concept of scalar or dot product.

Scalar product of two vectors can be obtained by finding the product of the magnitude of one vector and component of the other vector. Scalar products follow the commutative as well as distributive law.

**List of Topics in Chapter-6 “Work, Energy, and Power”**

- Introduction
- Notions Of Work And Kinetic Energy : The Work-energy Theorem
- Work
- Kinetic Energy
- Work Done By A Variable Force
- The Work-energy Theorem For A Variable Force
- The Concept Of Potential Energy
- The Conservation Of Mechanical Energy
- The Potential Energy Of A Spring
- Various Forms Of Energy : The Law Of Conservation Of Energy
- Power
- Collisions

**Chapter 7: System of Particles and Rotational Motion**

In this chapter, you will first understand that the constituent particles of a rigid body does not move at all, but vibrate in fixed positions. A rigid body fixed at one point only exhibit rotational motion. A non-fixed rigid body, on the other hand, exhibits either pure translatory motion or combination of translational and rotational motions.

Next topic in the queue revolves around angular velocity. In the previous chapter, we have already discussed scalar or dot product of two vectors. This chapter will introduce you to the vector or cross product of two vectors.

The most important topic of Chapter-7 revolves around the centre of mass of a system of n particles. Back exercise of this chapter includes questions that deploy the use of various formulae, including angular momentum, the torque of a system of n particles, etc.

**List of Topics in Chapter-7 “System of Particles and Rotational Motion”**

- Introduction
- Centre Of Mass
- Motion Of Centre Of Mass
- Linear Momentum Of A System Of Particles
- Vector Product Of Two Vectors
- Angular Velocity And Its Relation With Linear Velocity
- Torque And Angular Momentum
- Equilibrium Of A Rigid Body
- Moment Of Inertia
- Theorems Of Perpendicular And Parallel Axes
- Kinematics Of Rotational Motion About A Fixed Axis
- Dynamics Of Rotational Motion About A Fixed Axis
- Angular Momentum In Case Of Rotation About A Fixed Axis
- Rolling Motion

**Chapter 8: Gravitation**

To begin with, Newton’s law of universal gravitation is the core concept of Chapter-8 of NCERT Exemplar Class 11 Physics. It states that the gravitational force of attraction between two particles is directly proportional to the product of the masses and inversely proportional to the square of the distance between them.

Next, you will learn to find the resultant gravitational force acting on the particle (m) due to a number of masses M1, M2,...Mn. For this purpose, we will use the principle of superposition. Further, you will study Kepler’s laws of planetary motion in which you will learn to calculate period T and radius R of the circular orbit of a planet.

Recall the derivation of ‘acceleration due to gravity’, you can find the value of ‘g’ at a height h above the earth’s surface. The value of ‘g’ can also be found at depth ‘d’ below the earth’s surface using the equation given in this chapter.

**List of Topics in Chapter-8 “Gravitation”**

- Introduction
- Kepler’s Laws
- Universal Law Of Gravitation
- The Gravitational Constant
- Acceleration Due To Gravity Of The Earth
- Acceleration Due To Gravity Below And Above The Surface Of Earth
- Gravitational Potential Energy
- Escape Speed
- Earth Satellites
- Energy Of An Orbiting Satellite
- Geostationary And Polar Satellites
- Weightlessness

**Chapter 9: Mechanical Properties of Solids**

Chapter-9 “Mechanical Properties of Solids” begins with the discussion about stress and strain. Stress can be classified into three types- (a) tensile stress, (b) shearing stress, and (c) hydraulic stress. Proceeding further, we will study Hooke’s law and three elastic moduli to describe the elastic behaviour of objects.

The equation for Hooke’s law takes different forms under different conditions. There are three different conditions which include an object under tension or compression, deformation or hydraulic compression.

**List of Topics in Chapter-9 “Mechanical Properties of Solids”**

- Introduction
- Elastic Behaviour Of Solids
- Stress And Strain
- Hooke’s Law
- Stress-strain Curve
- Elastic Moduli
- Applications Of Elastic Behaviour Of Materials

**Chapter 10: Mechanical Properties of Fluids**

You are well-known about the fact that fluids have a tendency to flow. Fluids have a definite volume, but the indefinite shape, i.e., they take the shape of the container in which they are kept. A liquid is slightly compressible due to some spaces present between its constituent particles.

On the other hand, gases are highly compressible as there is no force of attraction between their constituent particles. Also, these particles lie far away from each other. Moreover, you will study two important laws which include Pascal’s law and Stokes’ law in the latter half of this chapter.

**List of Topics in Chapter-10 “Mechanical Properties of Solids”**

- Introduction
- Pressure
- Streamline Flow
- Bernoulli’s Principle
- Viscosity
- Surface Tension

Chapter 11: Thermal Properties of Matter

Chapter 11: Thermal Properties of Matter

You have already learnt the concept of heat in your earlier classes. To define, heat is a form of energy that flows between a body and its surrounding medium. You can represent the degree of hotness of an object with the help of temperature. Temperature can be measured in Kelvin, Celsius, and Fahrenheit. The SI unit of temperature is Kelvin.

As you proceed, you will obtain the relationship between Celsius and Fahrenheit temperature. Next comes the ideal gas equation that shows the connection between pressure, volume, and absolute temperature.

Questions present at the back of this chapter include problems asking you to find the specific heat capacity, latent heat of fusion, etc. Proceeding further, you will come across three modes of heat transfer- conduction, convection and radiation.

During the process of conduction, heat is transferred between constituent particles of a body through molecular collisions, without any flow of matter. The closing topic of this chapter revolves around Newton’s law of cooling.

**List of Topics in Chapter-11 “Thermal Properties of Matter”**

- Introduction
- Temperature And Heat
- Measurement Of Temperature
- Ideal-gas Equation And Absolute Temperature
- Thermal Expansion
- Specific Heat Capacity
- Calorimetry
- Change Of State
- Heat Transfer
- Newton’s Law Of Cooling

**Chapter 12: Thermodynamics**

Chapter-12 “Thermodynamics” will introduce you to three laws of thermodynamics, the zeroth, the first law and the second law. The zeroth law gave rise to the concept of temperature. Next, you will learn to calculate the internal energy of a system by adding the kinetic energies and potential energies of the molecular constituents of the system.

Moving on to the first law of thermodynamics, it adheres to the general law of conservation of energy in which energy is transferred from or to the surroundings. The second law of thermodynamics denies various processes consistent with the first law of thermodynamics.

In a quasi-static process, heat is either released or absorbed even though at every stage the gas has the same temperature as that of the surrounding reservoir.

**List of Topics in Chapter-12 “Thermodynamics”**

- Introduction
- Thermal Equilibrium
- Zeroth Law Of Thermodynamics
- Heat, Internal Energy And Work
- First Law Of Thermodynamics
- Specific Heat Capacity
- Thermodynamic State Variables And Equation Of State
- Thermodynamic Processes
- Heat Engines
- Refrigerators And Heat Pumps
- Second Law Of Thermodynamics
- Reversible And Irreversible Processes
- Carnot Engine

**Chapter 13: Kinetic Theory**

In this chapter, we will first discuss the ideal gas equation that connects absolute temperature, pressure, and volume. Moving forward, the kinetic theory of an ideal gas shows the relation between the number density of molecules, the mass of the molecule and mean of squared speed.

According to the law of equipartition of energy, if a system is in equilibrium at absolute temperature, energy distribution takes place equally in different energy modes of absorption. Using the formula of the mean free path, you can find out the average distance covered by a molecule between two successive collisions.

Other key concepts of Chapter-13 of NCERT Exemplar Class 11th Physics are translational kinetic energy, specific heat capacity, Maxwell distributive function, etc.

**List of Topics in Chapter-13 “Kinetic Theory”**

- Introduction
- Molecular nature of matter
- Behaviour of gases
- Kinetic theory of an ideal gas
- Law of equipartition of energy
- Specific heat capacity
- Mean free path

Chapter 14: Oscillations

Chapter 14: Oscillations

The opening topic of Chapter-14 is about periodic motion in which the object moves in a similar fashion at regular intervals of time. The wheels of a car exhibit periodic motion because the wheels rotate in a circular fashion. Next comes the concept of oscillatory motion in which an object exhibits to and fro motion.

The major difference between oscillatory and periodic motion is that a periodic motion may or may not be oscillatory, but the oscillatory motion is always periodic. Simple harmonic motion is a type of periodic motion where the amount of restoring force applied is directly proportional to the displacement from an equilibrium position.

**List of Topics in Chapter-14 “Oscillations”**

- Introduction
- Periodic And Oscillatory Motions
- Simple Harmonic Motion
- Simple Harmonic Motion And Uniform Circular Motion
- Velocity And Acceleration In Simple Harmonic Motion
- Force Law For Simple Harmonic Motion
- Energy In Simple Harmonic Motion
- Some Systems Executing Simple Harmonic Motion
- Damped Simple Harmonic Motion
- Forced Oscillations And Resonance

**Chapter 15: Waves**

Waves are characterized by disturbances caused in the air without the actual physical transfer or flow of matter as a whole. Next, you will learn to distinguish between transverse and longitudinal waves.

In a transverse wave, the particles travel perpendicular to wave motion. In the case of a longitudinal wave, particles of the medium travel in a direction parallel to the direction in which the wave particles move.

Next, you will study the equation of displacement in a sinusoidal wave that propagates in the positive x-direction. The third type of wave, namely, progressive wave is characterized by the movement from one point of medium to another. The wavelength of a progressive wave is the distance between two consecutive points of the same phase at a given time.

Later, you will find out that sound waves are longitudinal mechanical waves that can pass through solids, liquids or gases. Towards the end of this chapter, you will read about the doppler effect and the equation connecting observed frequency and source frequency.

**List of Topics in Chapter-15 “Waves”**

- Introduction
- Transverse and longitudinal waves
- Displacement relation in a progressive wave
- The speed of a travelling wave
- The principle of superposition of waves
- Reflection of waves
- Beats
- Doppler effect