Electricity is a fundamental aspect of modern life, powering our homes, businesses, industries, and technology. It’s a form of energy resulting from the movement of charged particles, typically electrons, through a conductor. Understanding the basics of electricity is important to understanding how various electrical systems work and how to use them safely and effectively.
Key Concepts:
Atoms and Charges: Atoms, the building blocks of matter, consist of protons (positively charged), neutrons (no charge), and electrons (negatively charged). An electric charge is created when electrons move from one atom to another. Materials can be classified as conductors, insulators, or semiconductors based on their ability to conduct electricity.
Voltage is the force or “push” that drives electric charges to move through a circuit. It’s measured in volts and symbolized by “V”. In other words, Voltage is the electric potential difference between two points in a circuit. It is the force that pushes electric current through a conductor. Voltage is measured in volts (V).
Current is the flow of electric charge through a conductor. It’s measured in amperes (amps) and symbolized by “I”. In other words, Current is the flow of electric charge through a conductor. It is measured in amperes (A). Current flows from the positive to the negative terminal in a circuit.
Resistance is the property of a material or component that restricts the flow of electric current, converting some of the electrical energy into heat. It depends on factors like the material’s properties, length, and cross-sectional area. The unit of resistance is the ohm (Ω). The relationship is described by Ohm’s Law: V=IR
The voltage across a conductor is directly proportional to the current passing through it, given that the temperature remains constant. Ohm’s Law describes the relationship between voltage, current, and resistance in an electrical circuit:
V= IR…………………(I)
Where:
An electric circuit is a closed path through which electric current flows. It typically consists of a power source (like a battery), conductors (wires), a load (like a bulb), and a switch. The current flows from the positive terminal of the source, through the circuit, and back to the negative terminal. For the circuit to work, it must be complete (closed).
A series circuit is a type of electric circuit where components are connected one after another in a single path. The same current flows through all components. If one component fails, the entire circuit stops working. The total resistance is the sum of individual resistances.
A parallel circuit is a type of electric circuit where components are connected across the same two points, creating multiple paths for current to flow. Each component gets the same voltage. If one component fails, the rest can still work. The total resistance decreases as more components are added.
Power is the rate at which electrical energy is transferred by an electric circuit. It’s measured in watts (W) and can be calculated using the formula:
Power = v*I …………………..(2)
Static electricity occurs when there’s an imbalance of positive and negative charges on an object. This imbalance can happen through various means, such as friction, induction, or conduction.
When these charges build up on an object, they can create a static electric field, which can cause effects like attraction or repulsion between objects, as well as phenomena like sparks or electric shocks.
Example: One simple example of static electricity is when you rub a balloon against your hair. When you do this, electrons from your hair are transferred to the surface of the balloon, leaving your hair with a positive charge and the balloon with a negative charge. Because opposite charges attract, the balloon will then stick to your hair or to a wall for a while due to the static electric force between the charged objects. This is a common demonstration of static electricity in action.
Dynamic electricity can be defined as the flow of electric charge through a conductor, typically in the form of an electric current.
This flow of charge can occur in various forms, including direct current (DC) and alternating current (AC).
In DC, the electric charge flows consistently in one direction, while in AC, the direction of the charge alternates periodically.
Dynamic electricity powers much of modern technology and infrastructure, including electrical appliances, lighting systems, motors, and electronics. It is the basis for electrical circuits and is governed by principles described by Ohm’s law and other electrical laws and theories.
Electricity has become an integral part of modern life, powering numerous devices, systems, and industries. Here are some key applications and uses of electricity:
Atoms are the basic building blocks of all matter. Each atom has a center called the nucleus, which contains protons and neutrons, and it is surrounded by tiny negatively charged electrons. The way these electrons are arranged decides the atom’s mass, charge, and how it reacts with other substances.
Atoms are composed of three subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the nucleus at the center of the atom, while electrons orbit the nucleus in electron shells or energy levels.
A proton is a positively charged particle found in the nucleus of an atom. It has a charge of +1 and a mass of approximately 1 atomic mass unit (amu). The number of protons in an atom determines its atomic number and identity.it is denoted by (p+)
A neutron is a neutral particle found in the nucleus of an atom. It has no electric charge and a mass nearly equal to that of a proton. Neutrons help stabilize the nucleus by balancing the repulsive forces between protons.. Neutrons have no charge.
An electron is a negatively charged particle that orbits the nucleus of an atom. It has a negative charge and a very small mass compared to protons and neutrons. Electrons are responsible for forming chemical bonds and conducting electricity. it is denoted by (e–)
The charge on an electron is 1.6×10-16 c.
The total weight of an atom is known as atomic weight. In other words, an atomic weight can be defined as the average weight of an element with respect to all its isotopes and their relative abundance. Atomic weight is measured in AMU or Dalton.
The atomic number can be defined as the total number of protons present in the uncles of an atom is called the atomic number. The total number of protons and neutrons present in the nucleus of an atom is called the mass number.
Electric charge can be defined as the amount of charge transferred from one body to another body through different models, such as conductors, induction, and specific methods. Electric charge can be categorized into two types, and these are positive electric charge and negative charge. The SI unit of electric charge is coulomb C.
Coulomb’s law states that the force of attraction or repulsion between two charges is directly proportional to the product of charges and inversely proportional to the square of the distance between the charges.
Let us consider two charges having magnitudes Q1 and Q2, which are separated by a distance of d meters, as shown below in diagrams
Mathematically, Coulomb’s law can be expressed as.
F ∝ Q1 *Q2 …………………………(1)
F ∝ 1/d2 …………………………..(2)
Now combining equations 1 and 2, we have
F =( k Q1 * Q2 )/ d2 …………………..(3)
Where:
Equation 3 is known as Coulomb’s law in mathematical form.
Numerical 1: Two point charges, 𝑞1=+3 μ, and 𝑞2=−5 μ are placed 10 cm apart in the air. Calculate the force between them.
solution.
Using Coulomb’s Law:
F = k Q1 * Q2 / d2 where is Coulomb’s constant (9×109N m2/C2).Substituting values:
F = (9 × 109 ) [(3x 10-6 ) × (5 x 10-6) / (0.1)2]
F= – 13.5N
Numerical 2:Two-point charges, q1 = +9 μC and q2 = 4 μC are separated by a distance d = 12 cm. What is the magnitude of the electric force?
Solution:
We know that,
F = k (q1q2 ∕ d2)
F = (9 × 109 ) [(9x 10-6 ) × (4 x 10-6) / (0.12)2]
F = (9 × 109 ) [36 × 10-12 /0.0144]
F = 22.5N
The electric force between the charges is approximately 22.5 N.
Numerical 3:Two point charges, 𝑞1=4 µC, and 𝑞2=−6 µC are placed 10 cm apart in the air. Calculate the magnitude of the electrostatic force between them.
Solution: Given:
We know that
F = k (q1q2 ∕ d2)
F= (9 × 109 ) [(4x 10-6 ) × (-6 x 10-6) / (0.1)2]
F = -21.6N.
All numerals are solved by Er. Basant Kumar yadav
An electric field is a region around a charged particle or object. Charged particles exert attractive forces on each other when their charges are opposite, and repulse each other when their charges are the same. The formula of the electric field is given as,
E = F /Q
Where,
An electric potential (also called the electrostatic potential) is the amount of electric potential energy that a unit Electric Flux: electric flux. the electric field potential or charge would have at any point in space, and is equal to the work done by an external agent in carrying a unit of positive charge from the arbitrarily chosen reference point (usually infinity) to that point without any acceleration.
An electric potential is the amount of work energy needed per unit of electric charge to move the charge from one place to another in an electric field. An electric potential is also called an electric field or electrostatics potential and is measured in volts.
An electric potential is the work done per unit charge to move a unit charge from one point to another in an electric field. Electric potential difference is also known as voltage, and electric potential difference is usually known as voltage difference, and its SI unit is volt.
Electric energy is the energy generated by the movement of electrons from one point to another. Generally, electrical energy is referred to as the energy that has been converted from electric potential energy. Electric potential energy is measured in joules or watt-hours.
The prime sources of electrical energy include renewable sources renewable sources like solar and wind, and nonrenewable sources like fossil energy fuels and nuclear power.
Hydropower is the main source of electrical energy in Nepal. Electrical energy is created from water stored in huge dams. The energy created by the water released from these dams is transformed into electricity by hydroelectric turbines and generators. Hydropower is the generation of electricity using the energy of moving water. Water from rivers or dams flows through turbines, causing them to spin and produce electricity. It is a renewable and clean source of energy. Hydropower plants are often built near water sources like rivers or waterfalls
Solar power is the energy generated from sunlight using solar panels.Solar panels contain photovoltaic (PV) cells that convert sunlight directly into electricity. It is a clean, renewable, and eco-friendly source of energy. Solar power reduces dependence on fossil fuels and lowers electricity bills. It works best in areas with strong and consistent sunlight.
Wind power is the energy generated by converting the wind’s kinetic energy into electricity using wind turbines. When the wind blows, it spins the turbine blades, which drive a generator to produce electricity. Wind power is renewable, clean, and produces no greenhouse gas emissions. It is often used in wind farms located in open or coastal areas with strong winds. Wind energy helps reduce reliance on fossil fuels and supports sustainable power generation.
