# Chapter 3 – Energy

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Introduction

Energy is a very important topic to be studied because something that we consume, eat, use is nothing but energy or at least it has energy included in it. You might have used the word “energy” a lot of time on a daily basis. Whenever you feel tired, you must be saying, “I don’t have enough energy to play another game”. But have you ever wondered what exactly energy is? You will be surprised to know that energy has different forms as well. Let us now study everything you need to know about energy.

#### What is Energy?

Energy is defined as the ability to do work. It is defined so because, in physics, energy is considered as a quantity that is transferred to an object for performing any work. Energy is a conserved quantity, and we will shortly learn about the law of conservation of energy. The SI unit of energy is Joule (J).

#### Units of Energy

Joule is the S.I unit of measurement of energy. Joule, the SI unit of energy, is named after James Prescott Joule. It is a derived unit that is equal to the energy spent in applying force 1 newton through a distance of 1 metre. There are also other units of energy like calories, ergs, kilowatt-hours le, British Thermal Units, kilocalories, etc. But these units require a conversion factor when expressed in SI units.

#### Conversion of Energy

The conversion of energy is in two forms: transfer and transform. When the energy moves from one location to another, it is called energy transfer. The energy keeps transferring all the time. There are four ways in which the energy can be transferred, and they are as followed:

1. Mechanically – By the action of force
2.  Electrically
3.  Radiation – By sound or light waves
4.  Heating – By Convection, Conduction, or Radiation

Energy transformation is a process that is the result of energy changing from one form to another form. Energy can be converted by transforming or transferring, but the amount of energy remains the same. This phenomenon is nothing but energy conservation. Let us now understand the law of conservation of energy.

#### Law of conservation of energy

One of the basic laws in physics and chemistry is the law of conservation of energy. It works on the microscopic motion of individual atoms in a chemical reaction. The law of conservation of energy states that “In a closed system, that is, a system that is isolated from its surroundings, the total energy of the system is conserved”. According to this law, even though the energy transformation occurs, the total energy in the system remains conserved. It simply means that energy can neither be created nor destroyed. It can only be transferred or transformed from one form to another.

#### Types of Energy

Energy has a lot of different forms, but it is broadly categorised as Kinetic and Potential energy.

Kinetic Energy

The energy that is associated with the motion of the object is called kinetic energy. When the objects are in motion, they are capable of doing work or causing change. To make it easier to understand, let us take an example of a big rolling stone; no matter how slow or fast it moves, it might destroy a few trees, whereas it does not do any work when it’s on rest. The formula to determine kinetic energy is as given below:

K. E = 1/2 x mv2

Types of kinetic energy:

• The energy which travels by particles or waves is called Radiant energy. It is an energy that is created through electromagnetic waves, and we humans usually experience it in the form of heat,
• For example, sunlight and an incandescent light bulb provide two forms of energy – we have visible light, and there is also the heat that is generated. Both of these energies are a form of Radiant energy.
1. Thermal Energy:
• As we learnt earlier, radiant energy refers to particles or waves, thermal energy is similar to Radiant energy, and it is experienced in the form of warmth or heat. There is only a small difference between Radiant energy and thermal energy: thermal energy describes the level of activity among the molecules and atoms in an object.
• For example, if you put the cake batter in the oven, you will raise the batter’s temperature. Eventually, the molecules which make up the cake start moving very quickly when the batter is hot.
1. Sound Energy:
When the vibration caused reaches the human ear, it is experienced as a sound by humans.
1. Mechanical Energy:
The energy associated with the mechanical movements of the objects is called mechanical energy.

#### Potential Energy

The energy which is stored in an object or a system of objects is called the potential energy. The potential energy is capable of transforming into a more obvious form of kinetic energy. The formula to determine potential energy is as given below:

P . E = m x g x h

Potential energy and kinetic energy forms mechanical energy, which is determined by the formula:

Mechanical Energy (M. E) = 1/2 x mv2 + mgh

Example: The example of potential energy is the water that is behind the dam.

Types of Potential energy:

Gravitational potential energy, elastic potential energy, chemical potential energy, electric potential energy, etc.

#### Conclusion

Energy is an important as well as an interesting topic. We successfully learnt about energy, units of energy, energy conversion, the law of conservation of energy, and different types of energy. To learn Energy in detail, you can refer to the video library by downloading the MSVgo app from the Google Play Store, iOS App Store, or read through the MSVgo website.

#### FAQs

1. Is work a type of energy?
A: Work is nothing but the transfer of energy. So, whenever we have 1 joule of energy transferred, we have 1 joule of work done.
2. Why is studying energy important?
A: All psychological processes and matter are composed of energy – emotions, thoughts, attitudes, beliefs, etc. For example, in the human body, every molecule, atom, tissue, cell, and body system has energy composed in it. Hence, it is important to study Energy.
3. Which unit of energy is used commercially?
A: Kilowatt-hour is the commercial unit of energy.
4. What happens to energy when the work is done on a body?
A:  The energy of the body increases.
5. What is the relation between Kinetic energy and potential energy?
A:  Increase in the kinetic energy is exactly equal to the decrease in the potential energy.

### High School Physics

• Alternating Current
• Atoms
• Communication Systems
• Current Electricity
• Dual nature of Radiation and Matter
• Electric Charges and Fields
• Electricity
• Electromagnetic Induction
• Electromagnetic Waves
• Electrons and Photons
• Electrostatic Potential and Capacitance
• Fluid Pressure
• Force and Acceleration
• Force And Laws Of Motion
• Gravitation
• Internal Energy
• Kinetic Theory
• Law of motion
• Light – Reflection And Refraction
• Magnetic Effects Of Electric Current
• Magnetism and Matter
• Management Of Natural Resources
• Mechanical properties of Fluids
• Mechanical properties of Solids
• Motion
• Motion in a plane
• Motion in a straight line
• Moving Charges and Magnetism
• Nuclear Energy
• Nuclei
• Oscillations
• Our Environment
• Paths of Heat
• Physical world
• Ray optics and optical instruments
• Semiconductor Devices
• Semiconductor Electronics: Materials, Devices and Simple Circuits
• Simple Machines
• Sound
• Sources Of Energy
• Specific and Latent Heats
• Spherical Mirrors
• Static Electricity
• Systems of Particles and Rotational motion
• Thermal properties of matter
• Thermodynamics
• Units and Measurement
• Vectors, Scalar Quantities and Elementary Calculus
• Wave Optics
• Waves
• Work, Power and Energy

### High School Chemistry

• Acids, Bases and Salts
• Alcohols, Phenols and Ethers
• Aldehydes, Ketones and Carboxylic Acids
• Aliphatic and Aromatic Hydrocarbons
• Alkyl and Aryl Halides
• Amines
• Analytical Chemistry
• Atomic Structure
• Atoms And Molecules
• Basic concepts of Chemistry
• Biomolecules
• Carbon And Its Compounds
• Carboxylic acids and Acid Derivatives
• Chemical Bonding and Molecular Structures
• Chemical Energetics
• Chemical Equilibria
• Chemical Kinetics
• Chemical Reactions And Equations
• Chemical Reactions and Their Mechanisms
• Chemistry in Everyday Life
• Chemistry of p-Block elements
• Chemistry of Transition and Inner Transition
• Classification of Elements
• Coordination Compounds
• Cyanide, Isocyanide, Nitro compounds and Amines
• Electrochemistry
• Electrolysis
• Elements, Compounds and Mixtures
• Environmental Chemistry
• Equilibrium
• Ethers and Carbonyl compounds
• Haloalkanes and Haloarenes
• Hydrocarbons
• Hydrogen
• Ideal solutions
• Introduction to Organic Chemistry
• Ionic equilibria
• Matter
• Matter Around Us
• Matter In Our Surroundings
• Metallurgy
• Metals And Non-Metals
• Mole Concept and Stoichiometry
• Natural Resources
• Organic Chemistry – Basic Principles
• Periodic Classification of Elements
• Physical and Chemical Changes
• Physical and Chemical Properties of Water
• Polymers
• Preparation, Properties and Uses of Compounds
• Principles and Processes of Isolation of Elements
• Redox Reactions
• Relative Molecular Mass and Mole
• States of Matter
• Structure Of The Atom
• Study of Compounds
• Study of Gas Laws
• Study of Representative Elements
• Surface Chemistry
• The d-block and f-block elements
• The Gaseous State
• The p-Block Elements
• The Periodic Table
• The s-Block Elements
• The Solid State
• Thermodynamics

### High School Biology

• Absorption and Movement of Water in Plants
• Anatomy of Flowering Plants
• Animal Kingdom
• Bacteria and Fungi-Friends and Foe
• Biodiversity and Conservation
• Biofertilizers
• Biological Classification
• Biomedical Engineering
• Biomolecules
• Biotechnology and its Applications
• Biotic Community
• Body Fluids and Circulation
• Breathing and Exchange of Gases
• Cell – Unit of Life
• Cell Cycle and Cell Division
• Cell Division and Structure of Chromosomes
• Cell Reproduction
• Cellular Respiration
• Chemical Coordination and Integration
• Circulation
• Control And Coordination
• Crop Improvement
• Digestion and Absorption
• Diversity In Living Organisms
• Ecosystem
• Environmental Issues
• Excretory Products and their Elimination
• Flowering Plants
• Genes and Chromosomes
• Health and Diseases
• Health and Its Significance
• Heredity And Evolution
• Heredity and Variation
• How Do Organisms Reproduce?
• Human Diseases
• Human Eye And Colourful World
• Human Health and Disease
• Human Population
• Human Reproduction
• Hygiene
• Improvement In Food Resources
• Integumentary System- Skin
• Kingdom Fungi
• Kingdom Monera
• Kingdom Protista
• Life Processes
• Locomotion and Movement
• Microbes in Human Welfare
• Mineral Nutrition
• Molecular Basis of Inheritance
• Morphology of Flowering Plants
• Neural Control And Coordination
• Nutrition in Human Beings
• Organism and Population
• Photosynthesis
• Photosynthesis in Higher Plants
• Plant Growth and Development
• Plant Kingdom
• Pollination and Fertilization
• Pollution; Sources and its effects
• Principles of Inheritance and Variation
• Reproduction and Development in Angiosperms
• Reproduction in Organisms
• Reproductive Health
• Respiration in Human Beings
• Respiration in Plants
• Respiratory System
• Sexual Reproduction in Flowering Plants
• Strategies for Enhancement in Food Production
• Structural Organisation in Animals
• Structural Organisation of the Cell
• The Endocrine System
• The Fundamental Unit Of Life
• The Living World
• The Nervous System and Sense Organs
• Tissues
• Transpiration
• Transport in Plants

### High School Math

• Algebra – Arithmatic Progressions
• Algebra – Complex Numbers and Quadratic Equations
• Algebra – Linear Inequalities
• Algebra – Pair of Linear Equations in Two Variables
• Algebra – Polynomials
• Algebra – Principle of Mathematical Induction
• Binomial Theorem
• Calculus – Applications of Derivatives
• Calculus – Applications of the Integrals
• Calculus – Continuity and Differentiability
• Calculus – Differential Equations
• Calculus – Integrals
• Geometry – Area
• Geometry – Circles
• Geometry – Conic Sections
• Geometry – Constructions
• Geometry – Introduction to Euclid’s Geometry
• Geometry – Three-dimensional Geometry
• Geometry – Lines and Angles
• Geometry – Straight Lines
• Geometry – Triangles
• Linear Programming
• Matrices and Determinants
• Mensuration – Areas
• Mensuration – Surface Areas and Volumes
• Number Systems
• Number Systems – Real Numbers
• Permutations and Combinations
• Probability
• Sequence and Series
• Sets and Functions
• Statistics
• Trignometry – Height and Distance
• Trignometry – Identities
• Trignometry – Introduction

### Middle School Science

• Acids, Bases And Salts
• Air and Its Constituents
• Basic Biology
• Body Movements
• Carbon and Its Compounds
• Cell – Structure And Functions
• Changes Around Us
• Chemical Effects Of Electric Current
• Coal And Petroleum
• Combustion And Flame
• Components Of Food
• Conservation Of Plants And Animals
• Crop Production And Management
• Electric Current And Its Effects
• Electricity And Circuits
• Elements and Compounds
• Fibre To Fabric
• Food production and management
• Force And Pressure
• Forests: Our Lifeline
• Friction
• Fun With Magnets
• Garbage In, Garbage Out
• Getting To Know Plants
• Health and Hygiene
• Heat
• Hydrogen
• Life Processes: Nutrition in Animals and Plants
• Materials: Metals And Non-Metals
• Matter and Its States
• Metals and Non-metals
• Micro Organisms: Friend And Foe
• Motion And Measurement Of Distances
• Motion And Time
• Nutrition In Animals
• Nutrition In Plants
• Organization in Living Things
• Our Environment
• Physical And Chemical Changes
• Pollution and conservation
• Pollution Of Air And Water
• Reaching The Age Of Adolescence
• Reproduction In Animals
• Reproduction In Plants
• Respiration In Organisms
• Rocks and Minerals
• Separation Of Substances
• Simple Machines
• Soil
• Some Natural Phenomena
• Sorting Materials Into Groups
• Sound
• Stars And The Solar System
• Structure of Atom
• Synthetic Fibers And Plastics
• The Living Organisms And Their Surroundings
• Transfer of Heat
• Transformation of Substances
• Transportation In Animals And Plants
• Universe
• Waste-water Story
• Water: A Precious Resource
• Weather, Climate And Adaptations Of Animals To Climate
• Winds, Storms And Cyclones

### Middle School Math

• Area and Its Boundary
• Boxes and Sketches
• Data Handling
• Fun With Numbers
• Heavy and Light
• How Many
• Long And Short
• Mapping
• Measurement
• Money
• Multiplication and Factors
• Multiply and Divide
• Numbers
• Parts and Wholes
• Pattern Recognition
• Patterns
• Play With Patterns
• Rupees And Paise
• Shapes And Angles
• Shapes And Designs
• Shapes and Space
• Similarity
• Smart Charts
• Squares
• Subtraction
• Tables And Shares
• Tenths and Hundredths
• Time