# Chapter 1 – Electric Charges and Fields

In this chapter Electric Charges and Fields, the following Topics and Sub-Topics are covered  and are available on MSVgo:

Static energy is a phenomenon which causes various daily life experiences that keep us wondering, “How did that happen?” For instance, charging of hair during combing, taking a sweater off in winters and experiencing a charge against the hair, or even lightning. This occurs when electric charges are discharged from our bodies and are accumulated due to the insulating surfaces rubbing against them. In Electric charges and fields, we will discuss such facts and explain the concept of Electrostatics, which is the advanced study of forces, fields, and potentials arising from static charges. It will cover concepts such as electric charge, conductors, insulators, Electric Dipole and Electric Field, etc.

#### Electric Charge

Electric Charge refers to the physical property of a matter, which causes a force in the matter when kept in an electromagnetic field. There are two types of electric charge, Positive and Negative. If there is an electric charge in an object, it is said to be electrified or charged, and when there is no charge, it is said to be neutral.

• Like charges repel each other.
• Unlike charges attract each other.
• Polarity of Charge – differentiates between the two types of charges.

#### Conductors and Insulators

Do you ever wonder why some substances get charged easily while others do not? This is due to their properties which distinguish them as Conductors and Insulators.

Conductors are substances which allow electricity to pass through them easily. This is due to the presence of electric charges (electrons) within them, which move around freely within the material. Metals, humans, animal bodies, and earth are examples of Conductors.

Insulators are the substances which do not allow electricity to pass through them easily and depict a high resistance to the passage of electricity. Substances such as glass, plastic, and wood are identified as Insulators.

#### Charging by Induction

In the process of charging by induction, a neutral conducting object is brought near a charged object with no physical contact between the two. The presence of charged objects near the neutral conductor forces the electrons within the conductor to move.

During the process of charging by induction, a charge is shared between two conductors when an uncharged conductor is brought in contact with a charged conductor. This way the uncharged conductor gets charged and both the objects acquire the same type of charge.

#### Coulomb's Law

Coulomb’s Law states that that the mutual electrostatic force existing between two point charges A and B is proportional to their product, which is AB, and inversely proportional to the square of the distance between them (r12).

where,

F = Force

R = Distance in Vacuum

q1 and q2 = Two point charges

K = 9*109Nm2C−2 Nm2C−2

#### Forces Between Multiple Charges

It is proven experimentally when taken one at a time, the force on any charge due to a number of other charges is the vector sum of all the forces on that charge due to the other charges. With the presence of other charges, individual forces are unaffected, which is termed as the principle of superposition.

Consider q1, q2 and q3 as three charges of a system. Here, if the force on q1 due to q2 is denoted by F12.

Where, F = electric force

K= 1/(4πε) = coulomb’s constant

q= charge

r= distance of separation

#### Basic Properties of Electric Charge

Charges are Additive in Nature – Charges can be added directly, and scalar in quantity, as they have only magnitude and no direction.

Algebraic sum for a system = q1 + q2 + q3 + q4 + … + qn

Where, q= charge

Charge is Conserved Quantity – Charges can neither be created nor be destroyed. They can only be transferred from one body to another through the means of conduction and induction.

Quantization of Charge – Charge is a quantized quantity and is expressed as integral multiples of the basic unit of charge (e – charge on one electron).

q = number of electrons/ protons * charge on one electron = ne

Here, n can be a positive or a negative integer.

#### Electric Field

An Electric Field is the physical field that surrounds each electric charge and exerts a force on all other charges in the field, either attracting or repelling them. Electric fields originate from electric charges or from time-varying magnetic fields.

• The electric force per unit charge is defined as Electric Field.
• It is radially outward from a positive charge and radially inward to a negative charge.
• Electric field is a vector sum.

Where

E = Electric Field

Q = Charge of Magnitude

R = Point of Distance

K = Constant value of 8.99 x 109 N m2/C2

#### Electric Dipole

A pair of equal and opposite point charges such as q and -q, separated by distance 2a is known as an Electric Dipole. The line connecting the two charges defines a direction in space. By convention, the direction from –q to q is said to be the direction of the dipole. The midpoint of –q and q is called the center of the dipole. The total charge of the electric dipole is obviously zero.

#### Gauss's Law

Gauss’s Law or Gauss’s Flux Theorem is a law relating the distribution of electric charge to the resulting electric field. The surface under consideration may be a closed one enclosing a volume, such as a spherical surface.

With the above discussion, we have learned a few basic concepts of Electric charges and fields. We have learned that an electric charge could be positive or negative like charges repel each other, and unlike charges attract each other. We have also learned about the process of charging through induction, Gauss’s Law, and Coulomb’s Law. But there is more in this topic that is left behind; which you can find on MSVgo and explore the world of electricity.

### 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
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• Ideal solutions
• Introduction to Organic Chemistry
• Ionic equilibria
• Matter
• Matter Around Us
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• Mole Concept and Stoichiometry
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• Periodic Classification of Elements
• Physical and Chemical Changes
• Physical and Chemical Properties of Water
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• 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