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 ↓


Current Electricity


Introduction

Current electricity means the flow of electrical charge in an electrical conductor. It is the steady flow of electrons through a conductor, which is usually a wire. Current electricity is important to understand because it powers everyday appliances, technology, and countless devices we depend on every day. Let's take a deeper dive into the world of current electricity and explore the key concepts, components, and applications.

Basic concepts

The basic concept of electric current revolves around the movement and flow of electric charges. These charges are generally electrons moving in a consistent direction, facilitated by a voltage difference. The main aspects we will explore include electric charge, electric current, voltage, resistance, and electric circuits.

Electric charge

Electric charge is a property of subatomic particles such as electrons and protons. Electrons carry negative charge, while protons carry positive charge. In metals, these electrons move around freely, which is responsible for electric current.

Electric current

Electric current is the rate at which electric charge passes through a point in a circuit. It is measured in amperes (A). When we talk about current, we are talking about the flow of electrons from one point to another. This can be visualized as water flowing through a pipe.

I = Q / t

In the above equation, I represents current in amperes, Q represents electric charge in coulombs, and t represents time in seconds.

Current flow Current direction

Voltage

Voltage, also called electric potential difference, is the force that causes electric charges to move through a circuit. It is similar to the pressure of water in a hose. Voltage is measured in volts (V).

The relationship between voltage (V), current (I) and resistance (R) in a circuit can be described by Ohm's law:

V = I * R

Resistance

Resistance is the resistance a conductor offers to the flow of electric current. It is measured in ohms (Ω). The higher the resistance, the more difficult it is for current to flow. Different materials have different levels of resistance.

Factors that affect resistance include the conductor's material, its length, cross-sectional area, and temperature. For example, longer conductors and conductors with a smaller cross-sectional area have higher resistance.

Obstructions A B

Components of the circuit

To build a complete circuit, several basic components are used. Each component has a specific function:

1. Power source

A power source, such as a battery or generator, provides the energy needed to move electrons through a circuit. The power source sets up a potential difference that causes current to flow.

2. Conductor

Conductors are substances that allow electrical charge to flow easily. Metals such as copper and aluminum are commonly used as conductors in circuits because they have low resistance and high conductivity.

3. Load

The load in a circuit is the component or device that uses electricity. This can include anything from a light bulb to a motor. The load converts electrical energy into other energy forms, such as light, heat, or motion.

4. Switch

A switch is a device that can open or close a circuit, thereby stopping or starting the flow of current. This allows easy control of electrical equipment and devices.

5. Connection wires

These wires connect various components of a circuit and are usually made of conductive material to ensure efficient flow of electricity.

Types of electric current

Electric current comes in two main forms: direct current (DC) and alternating current (AC). Understanding these types is important for defining the application and function of electrical systems.

Direct current (DC)

In direct current, the flow of electric charge is unidirectional, meaning it always flows in the same direction. A simple example would be electricity from a standard battery. Small devices such as flashlights and remote controls typically use DC.

,

Alternating current (AC)

Alternating current, on the other hand, changes direction periodically. This is the form of electricity that is usually supplied to homes and businesses. Alternating current is used in household electrical sockets because it is more efficient for distributing power over long distances.

Alternating waveform

Ohm's law

Ohm's law is a fundamental principle that describes the relationship between voltage, current, and resistance in an electric circuit. As explained earlier, this law is expressed as:

V = I * R

This equation states that the voltage across a conductor is equal to the product of the current flowing through it and the resistance of the conductor. Ohm's law is essential to the analysis and design of electrical and electronic circuits.

Example problem

Consider a simple circuit consisting of a 12 volt power supply and a 6 ohm resistor. We can use Ohm's law to find the current flowing in the circuit.

Given:

  • Voltage (V) = 12 V
  • Resistance (R) = 6 Ω

Solution:

Use of the formula:

I = V / R

Substituting the known values:

I = 12 V / 6 Ω = 2 A

Therefore, the current flowing in the circuit is 2 amperes.

Kirchhoff's laws

Kirchhoff's laws are two laws that deal with the conservation of charge and energy in electrical circuits.

Kirchhoff's current law (KCL)

This law states that the total current entering the junction must be equal to the total current leaving the junction. It is based on the conservation of electric charge.

Kirchhoff's voltage law (KVL)

This law states that the sum of the electric potential differences around any closed network is zero. It stems from the energy conservation principle.

Real-world applications

Current electricity powers many systems and technologies in the modern world. Here are some applications:

Light

Light bulbs convert electrical energy into light energy, which is a widespread use of current electricity in homes and public places.

Motors

Electric motors convert electrical energy into mechanical energy and are found in many appliances and industrial equipment.

Communication equipment

Electronics such as phones and computers depend on electricity to operate, making global communications and the exchange of information possible.

Conclusion

The study of electric current is vital to understanding how electrical systems work, both in theory and in practical technical use. From fundamental concepts such as voltage, current and resistance to circuit components and real-world applications, it provides a foundation for exploring the vast field of electrical engineering and physics.


Grade 10 → 5.2


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Current Electricity

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