# Chapter 8 – Electricity and Magnetism

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

Introduction

Let us begin with the introduction to electricity. In simple words, you can understand electricity as the presence and movement of charged particles. It is imperative to start understanding the basic electricity principles to help you answer your queries. The first step to understand the electricity concept is with the nature of matter. We have already studied that matter is made up of molecules, which are made up of atoms. Atoms are further composed of neutrons, protons, and electrons. Electricity can be dynamic or static. The two differ based on whether the electrons are in motion or at rest.

On the other hand, magnetism is a common concept in Physics that helps in the basic understanding of fundamental interactions in nature. Just like electrostatic force or gravitational force, the magnetic force is also interaction from a distance. In this chapter, we will study Electricity and Magnetism in detail.

#### Electric Current

In simple words, an electric current means the flow of charge. Charge carriers or moving electrons carry this charge in a wire. When we talk about current, we mean the movement of electrons to the positive battery terminal from the negative battery terminal through the circuit. The electric current is related to the resistance and voltage of the circuit.

#### Instruments Measuring Current

Various instruments are used to measure electric currents. Here are a few-

• Galvanometer- It is an instrument that measures a function of the current or a small electrical current by deflection of a moving coil. Detection Of Current By Galvanometer also measures the magnitude and direction of the current.
• Ammeter- It is another instrument that is used to measure the current in a circuit. The SI Unit of measuring current is amperes.  The Detection Of Current By Ammeter measures the magnitude of the current.

#### Sources of Direct Current

When discussing electric current, we also come across the concept of direct current. It can be defined as the unidirectional flow of current or electric charge. There are various sources of direct current. These are semiconductors, conductors like wire, and even through the vacuum. The rate of flow of charge is referred to as electric current. Ampere is the SI unit for measuring the rate of electric charge flow. It is equal to a charge that flows through the same surface at one coulomb per second.

• Conductors- Conductors are elements that allow the quick flow of electric charge. Thus, elements like copper, silver, and gold are good conductors, as they contain many free electrons. The atoms in these elements have electrons that are loosely bound in their outer orbits. These electrons break loose from the outer orbit and drift freely through the material. There is only one electron in the outer orbits of silver and copper elements, and there will be billions of free electrons in a piece of silver wire at room temperature.
• Insulators-  As the name suggests, insulators are materials that do not allow the electric charge flow. Examples of insulators are plastic, ceramic, and glass. Normally, atoms in these materials have no free electrons, which impedes electric current flow through them. Only if the material has a high and strong electric field does its outer electrons get dislodged.
• Semiconductors- These materials fall in between insulators and conductors. Some examples of semiconductors are germanium and silicon.

The direction of current is the direction in which the positive charge moves. Thus, the external circuit current moves away from the positive terminal towards the battery’s negative terminal.

#### Introduction to Magnetism

Magnetism is defined as the characteristic of the collective electromagnetic force. It is related to particular phenomena occurring from the magnetic force. Magnetic fields are created by objects that attract or repel other objects.

#### Earth's Magnetic Field

The Earth’s Magnetic Field is also referred to as the geomagnetic field. The Earth also has a magnetic field that covers millions of kilometres into outer space. The planet looks like a bar magnet, with its south magnetic pole near the North Pole, and the magnetic North Pole is close to Antarctica. Although the Earth’s magnetic field extends to a great distance, it is weak in terms of magnetic field strength. The rotation of our planet on its axis results in electric currents forming a magnetic field extending around the planet.

#### Cause of Earth's Magnetism

The theory of the Dynamo effect explains the cause of Earth’s magnetism. As per this theory, the planet gets its own magnetic field lines due to the presence of metallic fluids present in its inner and outer core. Molten iron is present in the outer core, while solidified elements are present in the inner core. Nickel and molten iron present in the inner core create convection currents responsible for the generation of Earth’s magnetism. These currents have charged particles that generate magnetic fields.

#### Conclusion

In conclusion, this chapter discusses electricity and magnetism in detail. Both electricity and magnetism are important concepts in physics. An electric current means the flow of charge, whereas magnetism is defined as the characteristic of the collective electromagnetic force.

#### FAQs

1. How does Induced Magnetism by bar magnet work?
The induced magnetism by Bar Magnet works and becomes a magnet only when it is positioned in a magnetic field. As soon as it is removed from the magnetic field, it loses its magnetism.
2. What is a Magnetic Compass?
The instrument used to determine direction on the Earth’s surface using a magnetic pointer that aligns itself with the magnetic field of the Earth is known as the Magnetic Compass. It is a popular surveying or navigational instrument.
3. What are Lines of Ma?
The lines of Ma are the field lines that indicate the direction pointed by a small compass when placed at a location.
4. What are conductors? Give a few examples.
Conductors are elements that allow the quick flow of electric charge. Thus, elements like copper, silver, and gold are good conductors, as they contain many free electrons.

When studying the Electricity and Magnetism Chapter, you will come across the topic discussed above. At MSVgo, you will find a video library that has well-curated videos on the topic. Watching them helps you easily understand the concepts. High-quality animations and visualisations will help clarify even complicated concepts in a way that the viewer understands them easily. For additional learning, do not hesitate to download this Android and an iPhone-compatible app that ensures learning on the go.

### 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