CBSE Class 10 Chapter 12 Science Notes: Electricity

Electricity Class 10 Notes

Electricity is the flow of electric current. It is a form of energy that can be generated, transmitted, and used for many purposes. We use electricity in almost every aspect of our lives. It powers everything from streetlights to home appliances like refrigerators and televisions to computers and smartphones. Electricity is used for lighting and heating purposes and power motorised machines such as fans or vehicles like cars or trains. Let us take a look at some important points in class 10 electricity notes.

Electric Current and Circuit

Current is the flow of electricity in a circuit. The current is measured in Ampere or amps. A current that is small and steady can be used to power small appliances like fans, lights, and radios. However, a large and uneven current can damage appliances or cause fires. Current flows through a wire in two directions: along the length of the wire and back through the junction (where the wire meets another wire). When current flows from the positive to negative ends of the wire, it is called a direct current (DC) because it goes straight from one point to another. DC currents change direction only once every second.

In a circuit, current can flow from one point to another via a wire, battery cable, motor, or other devices. For example, power flows from a generator to an outlet using a wire and a battery cable. Electric current can also flow through a material as heat energy passes through it. In this case, electric current is measured in watts (W) or joules per second (J/s).

Electric Potential and Potential Difference

Electric Potential and Potential Difference is a unit used to measure the amount of electricity that is flowing in a circuit. A positive voltage means that there is more electricity flowing than what is needed, while a negative charge means that there is not enough electricity flowing. Electric potential and potential difference are measured in volts or volts per meter and can be measured in either direction. An electric potential can be referred to as a potential drop, and a potential difference can be referred to as an electric potential difference or EPD.

When an object receives a charge, it gains electrons. This is called an electric current and causes a flow of electrons through the object’s circuits. When an object loses electrons, it creates a charge that results in a current in the opposite direction. This is known as an electric potential difference (EPD).

Electricity flows through wires when these two conditions are met: 1) A change in electric potential 2) An opposing current

This flow of electricity is determined by the voltage applied across the wires. The voltage applied across the wires determines their electric potential, which ultimately determines their electric current. In order to accurately measure the amount of electricity flowing through a wire, it must be first measured at one end (i.e., positive voltage) and then at the other end (i.e., negative voltage).

Ohm’s Law

Ohm’s Law of electrical resistance is a basic concept in electronics. This law states that the current flowing through an electrical device is directly proportional to the voltage applied across it.

It calculates the amount of current passing through a conductor and estimates its voltage.

When electricity flows through a wire, the electrons are pushed along by an electric field. When an electric field pushes on a mass, it moves that mass along in one direction but also experiences resistance to this motion. The opposing force of this movement against the mass is known as resistance, which causes it to heat up. The more resistance, the more energy must be expended in order to push the mass further. Since power = voltage × current, the greater the current, the greater the power (voltage).

This equation can be rewritten as:

P= I x R 

Note: I and R are interchangeable terms for current and resistance, respectively.

The cross-product between them measures how much work is being done against that resistance.

The equation can be rearranged as R = P/I

or R = P / I = V/I 

Solving for V requires using Ohm’s Law with two resistors connected in series. 

V = IR 

Factors on Which the Resistance of a Conductor Depends

Resistance is the opposition against the passage of a current. This resistance can be in the form of physical, chemical, or electrical resistance. Resistance is measured in Ohms (Ω). The higher the resistance of a conductor, the lower the current that flows through it. In electronics, low resistance is important because it allows current to flow efficiently. Lower resistance also means a longer life for electronic components.

Many factors influence the resistance of a conductor. These include:

  • Physical properties of a conductor, such as its thickness and composition
  • Chemical properties such as pH and ionic strength
  • Electrical properties such as electric field strength, temperature, contact area, etc.
  • Stresses and strains on the conductor
  • Any other external factors that affect the electrical characteristics of the conductor

Resistance of a System of Resistors

The resistance of a system of resistors in series and in parallel is the ratio between the DC resistance of each resistor. In simple terms, the larger the resistance value of a series-resistor circuit, the greater the resistance the DC current sees. The smaller the resistance value of a parallel-resistor circuit, the lesser the resistance seen by the DC current.

In series-resistor circuits, resistors are connected in a straight line, as shown below. The larger resistor has a greater resistance than the smaller one because it is physically smaller. In parallel-resistor circuits, resistors are connected side-by-side, as shown below. The smaller resistor has a smaller resistance than the larger one because it is physically closer to the ground than it is to the power supply (V).

Resistance values 1” are considered low and 10” are considered high for series-resistor circuits. Resistance values 1” are considered low and 10” are considered high for parallel-resistor circuits.

Heating Effect of Electric Current 

The electric current, when it flows through a conductor, generates heat. The heating effect is called thermal conductivity when the conductor is a metal. For example, copper conducts electricity three times faster than plastic. The greater the difference in temperature between the two materials, the greater the heat transfer rate.

The heating of an object increases with time if it is exposed to an electric current. The current not only raises the temperature of what it touches but also changes its shape by making it expand and contract. This movement causes friction, which in turn produces heat.

Electrical heating is best known as an electric stove or oven. In these appliances, a resistance wire (usually made of aluminium or cast iron) is submerged in water or oil and connected to a power source such as a wall socket or extension cord. This wire creates an electric current and transfers energy to the water or oil, causing them to get hotter and hotter until they boil and then eventually burn out.

To prevent your space from becoming too warm, use draft guards on doors and windows to keep cold air from infiltrating your home. 

Practical Applications of Heating Effect of Electric Current

The electric current flowing through the wires of a device creates a temperature difference. It can be used to heat or cool something or to change its surface properties.

It is one of the most commonly used forms of energy in our daily lives.

The heating effect of electric current can be applied to many different applications. These include heating and cooling food, cleaning and sterilising equipment, and even sterilising medical equipment.

Electric current can also be used for non-thermal purposes. For example, it can be used to create a magnetic field that attracts metal objects, and this allows people to pull metal from their hair without damaging their scalp.

The heating effect of an electric current is caused by the movement of ions in the wire. The ions move back and forth between the core and the surrounding material, creating thermal (heat) currents in both places. The amount of heat generated depends on the speed of these currents and their duration, as well as other factors such as the device’s size, shape and composition.

Electric Power Class 10 Science Electricity Notes

Electric power is the transmission of electrical energy from a source to a destination. It is one of the most important sources of energy in modern society. Power is used for many purposes, such as lighting, heating, cooling, transportation, telecommunications and industry. The SI unit of electric power is the watt (W).

Current methods for generating and transmitting electric power use transformers, inductors and capacitors to change electrical energy into usable voltages and currents. Electric power can be generated by using a variety of sources, such as fossil fuels like coal and natural gas, as well as renewable sources like solar and wind power. The primary transmission medium for electricity is electricity cables. In addition to providing power to homes and businesses, electricity transmits information through the electric power grid. This grid enables electrical devices such as computers, phones and appliances to exchange information with each other. The grid also provides backup power in the case of outages or accidents.


In class 10 science, we’ve learned a lot about how this powerful force works and how to harness it for our own purposes. Throughout our studies in ch 12 science class 10 notes, one thing has become clear: electricity is an incredible resource for individuals and society. But with great power comes great responsibility, and it is up to us to use it wisely and carefully going forward. Whether we’re working with cutting-edge scientific instruments or simply plugging in our phones at night, it will be up to us to help ensure that electricity continues playing its vital role in shaping the world we live in.