Grade 10
  1. Mechanics  1.1. Dynamics  1.1.1. Motion in one dimension  1.1.2. Motion in two dimensions  1.1.3. Displacement and Distance  1.1.4. Speed and Velocity  1.1.5. Acceleration  1.1.6. Graphical representation of motion  1.1.7. Equations of motion  1.1.8. Free fall and acceleration due to gravity  1.1.9. Projectile motion  1.1.10. Relative speed  1.2. Dynamics  1.2.1. Newton's Laws of Motion  1.2.2. Inertia and mass  1.2.3. Force and its types  1.2.4. action and reaction force  1.2.5. Friction and its effects  1.2.6. Coefficient of friction  1.2.7. Circular motion  1.2.8. Centripetal force and centripetal acceleration  1.2.9. Momentum and Impulse  1.2.10. Conservation of momentum  1.2.11. Newton's third law and applications  1.3. Work, Energy and Power  1.3.1. Work done by the force  1.3.2. Work–energy theorem  1.3.3. Kinetic energy  1.3.4. Potential energy  1.3.5. Mechanical energy  1.3.6. Energy Conservation  1.3.7. Power and efficiency  1.3.8. Renewable and non-renewable energy sources  1.4. Gravitational force  1.4.1. Newton's law of universal gravitation  1.4.2. Gravitational field and field strength  1.4.3. Acceleration due to gravity on different planets  1.4.4. Kepler's laws of planetary motion  1.4.5. Orbits and satellites  1.4.6. Weight and apparent weight  1.4.7. Gravitational potential energy
  2. Properties of matter  2.1. States of matter  2.1.1. Solid, liquid and gas  2.1.2. Molecular structure of matter  2.1.3. Intermolecular forces  2.1.4. Plasma and Bose–Einstein condensate  2.2. Pressure  2.2.1. Definition of Pressure  2.2.2. Pressure in liquids  2.2.3. Atmospheric pressure  2.2.4. Pascal's principle  2.2.5. Archimedes' Principle and Buoyancy  2.2.6. Surface tension and capillarity  2.3. Elasticity  2.3.1. Hooke's law  2.3.2. Stress and strain  2.3.3. Elastic Limit and Modulus of Elasticity  2.3.4. Applications of Elasticity
  3. Thermal physics  3.1. heat and temperature  3.1.1. Difference Between Heat and Temperature  3.1.2. Temperature scale  3.1.3. Thermal expansion  3.1.4. Thermal equilibrium  3.2. Heat transfer  3.2.1. Conductivity  3.2.2. Convection  3.2.3. Radiation  3.2.4. Insulation and its applications  3.3. Thermal properties of matter  3.3.1. Specific heat capacity  3.3.2. Latent heat and phase change  3.3.3. Boiling and Melting Point  3.3.4. Heat engines and refrigeration  3.4. Laws of Thermodynamics  3.4.1. Zeroth law of thermodynamics  3.4.2. First law of thermodynamics  3.4.3. Second law of thermodynamics  3.4.4. Carnot cycle
  4. Waves and optics  4.1. Nature and properties of waves  4.1.1. Types of waves in nature and properties of waves  4.1.2. Transverse and longitudinal waves  4.1.3. Wave parameters  4.1.4. Reflection and refraction of waves  4.1.5. Superposition and Interference  4.1.6. Standing Waves and Resonance  4.1.7. Doppler effect  4.2. Sound waves  4.2.1. Characteristics of sound waves  4.2.2. Speed of sound in different mediums  4.2.3. Applications of sound waves  4.2.4. Ultrasound and its uses  4.3. Light Waves and Optics  4.3.1. Nature of light  4.3.2. Reflection of light  4.3.3. Laws of reflection  4.3.4. Mirrors and Image Formation  4.3.5. Refraction of light  4.3.6. Snell's Law  4.3.7. Lenses and Image Formation  4.3.8. Total internal reflection and critical angle  4.3.9. Optical fibre  4.4. Optical Instruments  4.4.1. Microscope  4.4.2. Telescope  4.4.3. Human eye and vision defects  4.4.4. Camera and its working principle
  5. Electricity and Magnetism  5.1. Electrostatics  5.1.1. Electric charge and its properties  5.1.2. Conductors and Insulators  5.1.3. Coulomb's law  5.1.4. Electric field and field lines  5.1.5. Electric potential and potential difference  5.1.6. Capacitors and Capacitance  5.2. Current Electricity  5.2.1. Electric current and its measurement  5.2.2. Ohm's law  5.2.3. Resistance and resistivity  5.2.4. Series and Parallel Circuits  5.2.5. Electric power and energy  5.2.6. Kirchhoff's Laws  5.3. Magnetism and Electromagnetism  5.3.1. Magnetic field and field lines  5.3.2. Magnetic effects of electric current  5.3.3. Electromagnetic induction  5.3.4. Faraday's laws of electromagnetic induction  5.3.5. Transformers and Applications  5.3.6. AC and DC current
  6. Modern Physics  6.1. Nuclear physics  6.1.1. Structure of the atom  6.1.2. Bohr's atomic model  6.1.3. Electron Energy Levels  6.1.4. X-rays and applications  6.2. Radioactivity  6.2.1. Types of radiation  6.2.2. Half-life and radioactive decay  6.2.3. Nuclear reactions and applications  6.2.4. Fission and Fusion  6.3. Quantum physics  6.3.1. Wave–particle duality  6.3.2. Photoelectric effect  6.3.3. Energy quantization  6.3.4. Heisenberg's uncertainty principle
  7. Electronics and Communication  7.1. Semiconductors  7.1.1. Conductors, Insulators and Semiconductors  7.1.2. Diodes and their applications  7.1.3. Transistors and Logic Gates  7.1.4. LEDs and photodiodes  7.2. Communication Systems  7.2.1. Basics of communication  7.2.2. Analog and digital signals  7.2.3. Wireless and optical fibre communication  7.2.4. Radio Waves and Modulation

Grade 10 → Electricity and Magnetism → Electrostatics ↓


Conductors and Insulators


In physics, particularly in the field of electrostatics in electricity and magnetism, it is fundamental to understand conductors and insulators. This knowledge helps us determine how objects will interact with electric charges – will they conduct electricity, or will they resist it? Let’s look at these concepts in detail.

What are conductors?

Conductors are materials that allow electric charges to flow through them easily. In these materials, the outer electrons of the atoms are loosely bound and can move freely within the material. This free movement of electrons allows electricity to pass through the conductor with little resistance.

Examples of conductors

  • Metals: Most metals are excellent conductors. For example, copper and aluminum are widely used in electrical wiring.
  • Graphite: Unlike diamond, which is another form of carbon, graphite conducts electricity because of its structure, which allows free electrons.
  • Salt water: Because of the dissolved ions (charged atoms), salt water can conduct electricity.

Visual example of conductive materials

Conductor with free electrons (point)

What are insulators?

Insulators are materials that do not allow electric charges to pass through them easily. The electrons in insulators are tightly bound to their atoms and cannot move freely. Thus, electricity cannot pass through insulators as easily as it can through conductors.

Examples of insulators

  • Rubber: It is commonly used as a protective covering for wires and electrical equipment, preventing accidental electrical shocks.
  • Glass: It is used to prevent leakage of electricity in high voltage equipment.
  • Plastic: Widely used in household appliances and electrical insulation.

Visual example of insulating material

Insulator without free electrons

Conductivity and resistivity

Two important concepts when discussing conductors and insulators are conductivity and resistivity. Conductivity is a measure of how easily electricity can flow through a material, while resistivity is a measure of how much a material opposes the flow of electric current.

  • Conductivity ((sigma)): High conductivity means electricity flows easily. Conductors have high conductivity.
  • Resistivity ((rho)): High resistivity means that the material resists the flow of electricity. Insulators have high resistivity.
Conductivity = 1 / Resistivity Or Resistivity = 1 / Conductivity

Visual example of conductivity and resistivity

High conductivity, low resistivity (current flows easily) Low conductivity, high resistivity (current flows with difficulty)

How does temperature affect conductors and insulators?

Temperature can greatly affect both conductors and insulators. For conductors, increasing temperature generally increases resistivity because atoms vibrate more and create a greater barrier for free electrons. For insulators, increased temperature can sometimes decrease resistivity, because electrons gain enough energy to break free from the atoms and carry a charge.

Example

If you heat a metal wire (a conductor), its electrical resistance increases. Conversely, if you heat a glass rod (an insulator), the glass may begin to conduct a little electricity if it gets hot enough.

Comparison between conductors and insulators

Characteristic    Conductor    Insulator
-----------------------------------------------------------------------
Conductivity      High         Low
Free Electrons    Many         Few to none
Examples          Copper, Aluminum    Rubber, Quartz
Temperature Effect    Increases resistivity    Can decrease resistivity

Visual comparison

Conductor Insulator

Applications in real life

Understanding conductors and insulators is important for designing and using electrical systems. Here are some applications:

  • Electrical wires: Conductors such as copper are used for wires to efficiently transmit electrical current from one point to another.
  • Insulation materials: Insulators are used around wires and electrical parts to prevent accidental shocks and maintain safety.
  • Electronic components: Chips and circuit boards use a combination of conductors and insulators to control electrical currents.

Conclusion

Conductors and insulators play important roles in the flow of electricity. While conductors allow the free passage of electrical charges, insulators restrict it, providing safety and control in electrical systems. By understanding the properties and behaviours of these materials, we can effectively manage and use electrical energy in everyday life.


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Electric charge and its properties
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Coulomb's law

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Conductors and Insulators

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