# Chapter 11 – Light, Shadows And Reflections

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

Introduction

Light, shadows and reflection is a class 6th NCERT science chapter that introduces you to the world of light and its properties. Surprisingly, both mirrors and reflections are formed from light, but this happens due to their different properties. You must have seen that rainbows form after the rain- this phenomenon is due to reflection.

#### What is Light?

Light is a kind of electromagnetic radiation that can be detected by our naked eyes. Light is constituted of a bundle of rays that run in any one particular direction on a straight path. The speed of light has been calculated to be around 3 * 10^8 m/s. That’s tremendous speed, and due to this speed, property light can travel from the Sun to Earth in just 500 seconds. If you have a machine that can go with light speed, you will be in the sun until you complete one of our lesson video tutorials. That’s fantastic, isn’t it?

#### Luminous vs Non-Luminous Objects

All objects around us cannot produce light. Let’s see how we can categorise items based on this.

• Luminous Objects: Objects that produce their own light are called luminous objects. E.g., the sun, fire, etc.
• Non-luminous Objects: Objects that cannot produce their own light are called non-luminous objects, e.g., wood, table, pencil, etc. But if you burn wood, that would result in a fire, an example of luminous objects.

#### Rectilinear Propagation of Light

It’s a basic property of light that any ray of light travels in a straight direction. It cannot be bent without applying any external force. Hence we get the angles of incidence equal to the angle of reflection in the reflection topic.

Transparent, Opaque, and Translucent Objects

We can have different types of objects that behave differently when encountered with the light source. Let’s see their types below:

• Opaque object: These objects block the light completely and cast a shadow. No light ray can pass through the solid object, and hence a dark shadow is formed—e.g., wall, brick etc.
• Transparent object: In this type of object, light can pass through the surface of the object. Almost all light passes through these materials, for example- air and water.
• Translucent object: In this type of object, some light passes through it, and some is blocked completely. This comes in between the transparent and opaque objects—for example, butter paper.

#### What is Reflection?

Reflection is a natural physics phenomenon in which the light bounces back from the reflecting surface and changes its direction.

When you drop the ball on the floor, it bounces back. Why doesn’t it pass through the ground? This is because the floor acts as a medium of change of momentum for the ball. In optics, we can say this medium acts as a reflecting surface.

Hence, whenever a ray of light strikes a reflecting surface, there is the direction’s reversion, although the intensity remains the same if there is no external force and pressure on the ray of light. The momentum is conserved when the directions are reversed. We have a property in reflection as follows:

• The angle of incidence = angle of reflection.
• All the three entities, namely the angle of incidence, the normal, and the reflection angle, lie on the same plane.

#### Conclusion

Lights and shadows are very interesting phenomena in physics. Apart from them, we even have a reflection and refraction phenomenon. In submarines, we can see the surface through a device called a periscope. It uses the dual reflection method to get the view of levels different from viewers. The spectacles that we wear also use the properties of refraction to show you clear and distinct images. We can even make a pinhole camera using light properties. There are a lot of widely used optical instruments that help us in our daily lives.

#### FAQs

1.     What is the main difference between shadow and reflection?

Shadows are the projections of blocked lights on any surface. At the same time, reflections are the lights being reflected when hitting any surface and forming an image on the surface.

1.     What is the reflection for class 6th?

Reflection is a natural phenomenon where the light hits a reflecting surface and bounces back in proportion to the angle of incidence. When you stand in front of the mirror, your image is reflected, and hence you can see your beautiful face.

1.     What are the types of shadow?

The shadows can be divided into three parts based on the source of light. These are umbra, penumbra, and antumbra.

1.     Can we see a shadow even if there is light?

Shadows are formed in the presence of light. When the light is blocked from any object, then a shadow is cast. Hence we can see shadows in the presence of light. For example, in the daytime, you find the leaves’ shadows under the tree.

1.     Is a shadow a reflection?

No shadows are not a reflection as there are different ways the light is treated in both. In shadows, light is blocked, whereas, in reflection, the lights are bounced back.

Shadows are dark shaped images formed on a surface when light is blocked from any solid object.

You can find detailed video explanations for the topic reflection and shadows from MSVgo, and learn using intuitive videos. The videos will also explain how refraction is found in spectacles and other such relatable objects.

### 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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• Metallurgy
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• Mole Concept and Stoichiometry
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• Organic Chemistry – Basic Principles
• 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
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• 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