Chemical Reactions and Equations
- Chemical Equation
- Balancing Chemical Equation
- Types of Chemical Change or Chemical Reaction
- Direct Combination (or Synthesis) Reaction
- Decomposition Reactions
- Single Displacement Reactions
- Double Displacement Reaction
- Oxidation, Reduction and Redox Reactions
- Corrosion of Metals and Its Prevention
- Rancidity of Food and Its Prevention
Chemical Substances - Nature and Behaviour (Chemistry)
Acids, Bases and Salts
- Bases (Alkalis)
- Properties of Acids
- Properties of Bases (Alkalis)
- Acid or a Base in a Water Solution
- Similarities and Differences Between Acids and Bases
- Strength of Acidic or Basic Solutions
- Important Salts in Daily Life
- Preparation and Uses of Sodium Hydroxide
- Preparation and Uses of Bleaching Powder
- Preparation and Uses of Baking Soda
- Preparation and Uses of Washing Soda
- Preparation and Uses of Plaster of Paris
World of Living (Biology)
Metals and Non Metals
- Types of Elements: Metals
- Physical Properties of Metals
- Chemical Properties of Metal
- Types of Elements: Non-metal
- Physical Properties of Non-metal
- Chemical Properties of Non-metal
- Electrovalent (or Ionic) Bond
- Reactivity Series of Metals
- Extraction of Metals
- Refining of Metals
- Corrosion of Metals and Its Prevention
- The Covalent Bond
Natural Phenomena (Physics)
Carbon and its Compounds
- Carbon: a Versatile Element
- The Covalent Bond
- Saturated and Unsaturated Carbon Compounds
- Allotropy and Allotropes of Carbon
- Crystalline Allotropes of Carbon: Diamond
- Crystalline Allotropes of Carbon: Graphite
- Crystalline Allotropes of Carbon: Fullerene
- Chains, Branches and Rings of Carbon Compound
- Functional Groups in Carbon Compounds
- Homologous Series of Carbon Compound
- Nomenclature of Organic Compounds (IUPAC)
- Chemical Properties of Carbon Compound
- Ethanoic Acid
- Cleansing Action of Soap
Effects of Current (Physics)
Periodic Classification of Elements
- History of Periodic Table: Early Attempts at the Classification of Elements
- Dobereiner’s Triads
- Newland's Law of Octaves
- Mendeleev’s Periodic Table
- Merits and Demerits of Mendeleev’s Periodic Table
- The Modern Periodic Table
- Periodic Properties
- Periodic Properties: Valency
- Periodic Properties: Atomic Radius Or Atomic Size
- Periodic Properties: Metallic Character
- Periodic Properties: Non-metallic Character
- Living Organisms and Life Processes
- Nutrients and Nutrition
- Mode of Nutrition in Plant
- Autotrophic Nutrition
- Heterotrophic Nutrition
- Different Ways of Taking Food
- Human Digestive System
- The Mouth and Buccal Cavity
- The Teeth and Its Structure
- The Salivary Glands
- Swallowing and Peristalsis
- The Food Pipe/Oesophagus
- The Stomach
- The Small Intestine
- Absorption of Food
- The Large Intestine
- Assimilation of Food
- Respiration in Organisms
- Breathing in Other Animals
- Types of Respiration: Aerobic and Anaerobic Respiration
- Human Respiratory System
- Composition of Blood: Plasma (The Liquid Portion of Blood)
- Composition of Blood: Red Blood Cells (Erythrocytes)
- Composition of Blood: White Blood Cells (Leukocytes)
- Composition of Blood: Blood Platelets (Thrombocytes)
- Blood Circulatory System in Human
- Human Heart
- Blood Vessels – Arteries, Veins, and Capillaries
- Circulation of Blood in the Heart (Functioning of Heart)
- Types of Blood Circulation
- Heart Beat - Heart Sounds "LUBB" and "DUP"
- Function of Platelets - Clotting of Blood (Coagulation)
- Lymph and Lymphatic System
- Blood Pressure (B.P.)
- Transportation of Water and Food in Plants
- Water and Mineral Absorption by Root
- Translocation of Water (Ascent of Sap)
- Translocation of Mineral Ions
- Transport of Food
- Excretion: Substances to Be Eliminated
- Human Excretory System
- Function of the Kidney - “Production of Urine”
- Excretion in Plants
Control and Co-ordination
- Control and Co-ordination in Animals
- Human Nervous System
- Neuron (Or Nerve Cell) and Its Types
- Neuron as Structural and Functional Unit of Neural System
- Nerve Fibres
- Major Division of the Nervous System
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
- The Human Brain
- Central Nervous System (CNS): Structure of Human Brain
- Reflex and Reflex Action
- Nervous Pathways in Reflexes
- Reflex Arc
- Co-ordination in Plant: Tropism in Plants
- Plant Hormones
- Types of Plant Hormones: Auxins
- Types of Plant Hormones: Gibberellins
- Types of Plant Hormones: Ethylene
- Types of Plant Hormones: Cytokinins
- Types of Plant Hormones: Abscisic Acid (ABA)
- Types of Plant Hormones: Ethylene
- Hormones in Animals
- Human Endocrine System
- Pituitary Gland or Hypophysis Gland
- Thyroid Gland
- Parathyroid Gland
- Pancreas (Islets of Langerhans)
- Adrenal Gland (Suprarenal Gland)
- Reproductive Glands (Gonads)
- Thymus Gland
How do Organisms Reproduce?
- Accumulation of Variation During Reproduction
- Reproduction in Plant
- Mode of Reproduction in Plant
- Asexual Reproduction in Plant
- Natural Vegetative Reproduction
- Sexual Reproduction in Flowering Plants
- Sexual Reproduction in Animals
- Human Reproductive System
- The Male Reproductive System
- The Female Reproductive System
- Menstrual Cycle (Ovarian Cycle)
- Reproductive Health
- Sexually Transmitted Diseases (STD)
Heredity and Evolution
- Accumulation of Variation During Reproduction
- Gregor Johann Mendel – Father of Genetics
- Inheritance of One Gene (Monohybrid Cross)
- Inheritance of Two Genes (Dihybrid Cross)
- Mendelian Inheritance - Mendel’s Laws of Heredity
- Sex Determination
- Lamarck’s Theory of Evolution
- Darwin’s Theory of Natural Selection
- Theories of Origin of Life
- Evolution and Classiffication
- Evidences for Biological Evolution
- Evolution by Stages
- Origin and Evolution of Man
Light - Reflection and Refraction
- Reflection of Light
- Law of Reflection of Light
- Mirrors and Its Types
- Plane Mirror and Reflection
- Spherical Mirrors
- Rules for the Construction of Image Formed by a Spherical Mirror
- Images Formed by Spherical Mirrors
- Concave Mirror
- Image Formation by Concave Mirror
- Convex Mirror
- Image Formation by Convex Mirror
- Sign Convention for Reflection by Spherical Mirrors
- Mirror Equation/Formula
- Linear Magnification (M) Due to Spherical Mirrors
- Refraction of Light
- Refraction of Light Through a Rectangular Glass Slab
- Law of Refraction of Light
- Refractive Index
- Spherical Lens
- Images Formed by Sperical Lenses
- Guideline for Image Formation Due to Refraction Through a Convex and Concave Lens
- Concave Lens
- Images Formed Due to Refraction Through a Concave Lens
- Convex Lens
- Images Formed Due to Refraction Through a Convex Lens
- Sign Convention for Spherical Lenses
- Lens Formula
- Magnification Due to Spherical Lenses
- Power of a Lens
The Human Eye and the Colourful World
- Human Eye: Structure of the Eye
- Working of the Human Eye
- Eye Defect and Its Correction: Myopia Or Near-sightedness
- Eye Defect and its correction: Hypermetropia or far-sightedness
- Eye Defect and Its Correction: Presbyopia
- Care of the Eyes
- Refraction of Light Through a Prism
- Concept of Prism
- Dispersion of Light Through Prism and Formation of Spectrum
- Atmospheric Refraction
- Application of Atmospheric Refraction
- Scattering of Light and Its Types
- Applications of Scattering of Light
- Electric Current
- Electric Circuit
- Potential and Potential Difference
- Symbols and Functions of Various Components of an Electric Circuits
- Ohm's Law
- Factors Affecting the Resistance of a Conductor
- Electrical Resistivity and Electrical Conductivity
- Resistors in Series
- Resistances in Parallel
- Effects of Electric Current
- Heating Effect of Electric Current
- Electrical Power
Magnetic Effects of Electric Current
- Magnetic Effect of Electric Current
- Magnetic Field
- Magnetic Field Lines
- Magnetic Field Due to a Current Carrying Straight Conductor
- Rule to Find the Direction of Magnetic Field
- Magnetic Field Due to Current in a Loop (Or Circular Coil)
- Magnetic Field Due to a Current Carving Cylindrical Coil (or Solenoid)
- Force on a Current Carrying Conductor in a Magnetic Field
- Electric Motor
- Electromagnetic Induction
- Faraday's Laws of Electromagnetic Induction
- Electric Generator
- Alternating Current (A.C.) Generator
- Direct Current Motor
- Household Electrical Circuits
- Distinction Between an A.C. Generator and D.C. Motor
- Types of current: Alternating Current (A.C.) and Direct Current (D.C.)
Sources of Energy
- Source of Energy
- Conventional Sources of Energy and Non-conventional Sources of Energy
- Fossil Fuels
- Heat Energy (Thermal Energy)
- Hydroelectric Energy
- Wind Energy
- Solar Energy
- Solar Energy Devices
- Energy from the Sea
- Geothermal Energy
- Nuclear Energy
- Nuclear Fission
- Different Forms of Energy
- Environmental Consequences
- How Long Will an Energy Source Last Us?
Sustainable Management of Natural Resources
- Sustainability of Natural Resources
- Case Study: Ganga Pollution and Ganga Action Plan
- Solid Waste Management
- Five R’s of Waste Management
- Conservation and Judicious Use of Resources
- Forests: Our Lifeline
- Stakeholders of Forest
- Conservation of Forest
- Conservation of Wildlife
- Water Management (Conservation of Water)
- Fresh Water Management
- Non-crystalline/Amorphous Forms: Coal
- Conservation of Coal, Petroleum, and Natural Resources
- Overview of Natural Resource Management
Uses of concave mirror:
When a concave mirror is held near the face such that the face is between the pole and the focus of the concave mirror, the mirror forms an upright and magnified image. So even the tiny hairs on the facecan easily be seen. For this a concave mirror of large focal length ( so that the face always lie between its focus and the pole) and large aperture ( so as to view the entire face) is used.
If a parallel beam of light is incident on a concave mirror, it is focuses the beam of light to a point. This fact enables us to use it as a doctor's head mirror to concentrate the beam of light on a small area of the body part to be examinedsuch as teeth, nose, throat and ear etc.
For this a parallel beam of light is made to fall on the concave mirror attached to the band tied at the fore head of doctor examining the body part.
In torch light, search light and head lights of the vehicles a concave highly polished metallic surface is used as a reflector to obtain a parallel beam of light to focus at the longer distance.
For this, the source of light (i.e., bulb) is placed at the focus of the concave reflector ( mirror). The rays of light incident on the concave reflector from the bulb after reflection from a parallel beam.
Uses of Convex Mirror
A convex polished metallic surface is used in street lamp as a reflector so as to diverge light over a larger area.
Rear View Mirror
Convex mirrors are used as rear view mirrors in vehicles.
A driver prefers to use a convex mirror as a rear view mirror because of the following two reasons
A convex mirror always produces an erect image of the objects.
The images formed in a convex mirror is highly diminished or much smaller than the objec, due to which a convex mirror gives a wide field of view of the traffic behind.
Shop Security Mirrors
By placing a big convex mirror at a strategic point in the shop, the shop owner or the manager can keep an eye on the customers to look for thieves and shop lifters among them.
Uses of Convex Lenses
- Convex lenses are used in spectacles to correct the defffective vision called hepermetropia or longsightedness.
Convex lens is used for making a simple camera.
Convex lens is used as a magnifying glass (or magnifying lens)(by palmists, watchmakers, etc.).
Convex lens is used in making microscopes, telescopes and slide projectors (or film projectors).
Uses of Concave Lenses
- Concave lenses are used in spectacles to correct the defect of vision called myopia (or shortssightedness).
Concave lens is used as eye-lens in Galilean telescope.
Concave lenses are used in combination with convex lenses to make high quality lens systems for optical instruments.
Concave lens is used in wide-angle spyhole in doors.
Types of Mirror:
Plain Mirror: A mirror having a flat surface is called plane mirror.
Formation of image in plane mirror:
A plane mirror always forms virtual and erect image.
The distance of image and that of object is equal from the mirror.
The image formed by a plane mirror is laterally inverted
Spherical Mirror: Mirrors having curved reflecting surface are called spherical mirrors. A spherical mirror is a part of a sphere.
Types of Spherical Mirror:
Concave Mirror: Spherical mirror with reflecting surface curved inwards is called concave mirror.
Convex Mirror: Spherical mirror with reflecting surface curved outwards is called convex mirror.
Important terms in the case of spherical mirror:
Pole: The centre of reflecting surface of a spherical mirror is known as Pole. Pole lies on the surface of spherical mirror. Pole is generally represented by ‘P’.
Centre of Curvature: The centre of sphere; of which the reflecting surface of a spherical mirror is a part; is called the centre of curvature of the spherical mirror. Centre of curvature is not a part of spherical mirror rather it lies outside the mirror. Centre of curvature is denoted by letter ‘C’.
In the case of concave mirror centre of curvature lies in front of the reflecting surface. On the other hand, centre of curvature lies behind the reflecting surface in the case of convex mirror.
Radius of Curvature: The radius of sphere; of which the reflecting surface of a spherical mirror is a part; is called the Radius of Curvature of the spherical mirror. The radius of curvature of a spherical mirror is denoted by letter ‘R’.
Similar to centre of curvature, radius of curvature lies in front of concave mirror and lies behind the convex mirror and is not a part of the mirror as it lies outside the mirror.
Aperture: The diameter of reflecting surface of a spherical mirror is called aperture.
Focus or Principal Focus: Point on principal axis at which parallel rays; coming from infinity; converge after reflection is called the Focus or Principal Focus of the spherical mirror. Focus is represented by letter ‘F’.
Principal Axis: Imaginary line passing through the centre of curvature and pole of a spherical mirror is called the Principal Axis.
In the case of a concave mirror, parallel rays; coming from infinity; converge after reflection in front of the mirror. Thus, the focus lies in front of a concave mirror.
In the case of a convex mirror, parallel rays; coming from infinity; appear to be diverging from behind the mirror. Thus, the focus lies behind the convex mirror.
Focal length: The distance from pole to focus is called focal length. Focal length is denoted by letter ‘f’. Focal length is equal to half of the radius of curvature.
- Spherical Mirrors
- Terms related to Spherical Mirrors
- Center of Curvature (C)
- Pole (P)
- Radius of Curvature (R)
- Principal Axis
- Focus (F)
- Focal length (f)
- Principal section
Shaalaa.com | Light Reflection and Refraction part 3 (Spherical Mirror)
Series: series 1
A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?
(A) He should move the mirror away from the screen.
(B) He should move the mirror slightly towards the screen.
(C) He should move the mirror as well as the screen towards the newly selected object.
(D) He should move only the screen towards the newly selected object.
State the types of mirrors used for (i) headlights and (ii) rear view mirror, in cars and motorcycles. Give to justify your answer in each case.
If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens?
A student obtains a sharp image of the distant window (W) of the school laboratory on the screen (S) using the given concave mirror (M) to determine its focal length. Which of the following distances should he measure to get the focal length of the mirror?
A student traces the path of a ray of light passing through a rectangular slab.
For measuring the angle of incidence, he must position the protractor in the manner shown in the figure: