Sources of Energy, Class 10 Notes and, Introduction

    In this article, we will talk about (sources of energys). This article is especially for those people who like to study more online. In this article, all topics have been told very clearly. Which will help you a lot in your online learning.

    What is Energy –

    In everyday language, we use the word energy. Throughout the day, a laborer performs physical work and his energy decreases when he is tired in the evening.

    He relaxes and eats and regains energy. Often we say that a glass of orange juice has great energy.

    On falling ill, energy is obtained by using tonics. Similarly, by eating food, using fruit juices and tonics, we get energy which gives us the ability to work again. Similarly, coal, petrol, wood etc. are the fuel from which the machines get the ability to work

     Sources of Energy

    Therefore, energy is one of the factors that is required to work. “When an object has the ability to function,we can say that the object has energy.


    ” No fundamental definition of energy can be given, can only be said that the reason why an object has the ability to work It is called energy. That is, the ability to work is called energy.

    Sources of Energy:-

    Different types of energy, from where we get them, we call them related energy sources. Heat is mixed with the burning of coal, so coal is a source of thermal energy. 

    Power – The chemical energy in the cell is obtained by electrical activity. Hence, cell is the source of electrical energy.

    Various kinds of energy can be changed over into one another. There are different sources of energy in nature.


    1. (Sources of Energy)Fuel wood, coal, petrol, diesel etc.

    We have been using thermal energy since time immemorial. We use heat in cooking, making weapons from metals like iron and to protect ourselves from cold. In the stone and iron-age heat, we got heat from burning wood and coal.

    Over time, work was done with the thermal energy obtained from burning coal in external combustion engines. In internal combustion engines,

     petrol and diesel are used as energy sources. We know that work can be done by converting thermal energy into light energy and electrical energy.

    Hence, wood, coal, petrol, diesel etc. are known as sources of chemical energy, thermal energy and electrical energy etc.


    2. (Sources of Energy)Running water: –

    Water falls at high speed through the springs on the mountains. The flowing and falling water have mechanical energy. 

    This mechanical energy is converted into electrical energy by hydropower generating plants. Water moving in the form of ocean waves is also a means of obtaining electric energy.

    Rainwater is collected in large reservoirs. They drop this water from a height. This produces mechanical energy which can be converted into electrical energy. 

    With the power collected from the water collected in the reservoirs through the Rihand Dam, Bhakra Nangal Dam, etc., we undertake a lot of work. Thus, water is a major source of energy.

    3. Wind / flowing wind: –

    Flowing air is also a major source of energy. Since ancient times, windmills are being run by air only. Windmills also produce electricity. Thus, wind is also a natural energy source.


    4. Sun:-

    The Sun is the essential source of energy for the Earth. We get thermal energy and light energy from the sun. Now electric energy is also being obtained by this. The rays of the sun are put on the solar cell. These solar cells are made of electric semiconductors.


    And they collect the energy inside them as solar energy. This solar energy is converted into electrical energy and uses it in water pumps, radios, solar cookers, television etc.

    Electrical Energy

    Power – Energy:-

    In general language, it is called Electric, it is a type of energy. The electrical energy comes from the electrochemical cell (dry cell used in flashlight, accumulator cell used in motor-cars etc.), light-voltaic cell (solar-battery) and (electric dynamo).

    All these devices are means of generating current. Electric energy can be used only through electric current. Therefore, to understand the origin and use of electric energy, it is necessary to study the current.

     Sources of electrical energy 

    (1) Electric generator – 

    Dynamo is an electric device that converts mechanical energy into electrical energy. In this, a closed coil is rotated in the magnetic field, which generates electric energy due to electromagnetic induction.

    (2) Power cell – 

    An electric cell is an electrical process in which chemical energy is converted into electrical energy. Examples – Dry cell, Leclanse cell, Daniel cell, Lead accumulator cell, etc.

    (3) Light – 

    Power cell – The electric process that converts light energy into electrical energy is called light power cell. In this, an electric current is generated by the flow of electrons emitting ultraviolet rays onto the cesium or potassium. 

    Solar batteries also operate on the same principle. Nowadays they are being used in spacecraft, artificial satellites, etc.


    (4) Heating-pairing –

     Heating-pair is an electrical device in which the ends of two different metals such as antimony and wismat together form a closed circuit and keep the two joints of this circuit at different temperatures.

     Due to which electric force is generated in the circuit and electric current starts flowing in the circuit.


    Electric charge and current – 

    According to the modern theory of the structure of electric charge, all atoms of matter are made up of three types of radicals.

    (1) electrons, (ii) protons and (iii) neutrons 

    The part at the center of the atom is called nucleus. The core of an atom comprises of protons and neutrons. Electrons rotate around the nucleus.

     The movement of the electron around the nucleus means that an attraction force acts between the nucleus and the electron which accelerates the electron towards the nucleus.

    It is known by experiments that the force of attraction is between the protons and the electrons. And it is also known that two protons or two electrons repel each other.

    This repulsive attraction force between two protons, two electrons, or a proton-electron is called an electric force.

    Electrical conductors, electric conductors, and semiconductors –

    Wrap a piece of rubber on a brass rod and hold it in such a way that there is no direct contact of the hand with the rod. Now by rubbing the brass rod with wool and checking its cover to small pieces of paper, it is known that the brass rod attracts a piece of paper.

    Now after removing the rubber piece, take the brass rod directly in the hand and rub the rod again with wool and check its charge, it is known that the rod is not charged.

    This experiment leads to the conclusion that the brass rod was charged in the second position, but due to direct contact with the hand of the rod, 

    the charge was transferred from the brass rod. When a piece of rubber came between the hand and the rod, the charge could not be transferred through the rubber.

    The substances in which the electric current goes from one end to the other are called electrical conductors. Earth, all metals and acids, bases and salts are the electrical conductors of aqueous solutions.

    Conversely, materials that do not allow the charge to pass through them or that do not transfer charge through it are called electrical conductors or insulators, such as rubber, mica, dry wood, plastic. , Glass, ceramic, paper etc.

    Pure distilled water is also a conductor of electricity, but when added to it a little acid, alkali or salt, it acts like an electric conductor.

    In addition, there are also some substances that normally behave like non-conducting but behave like conductors under special physical conditions

     such as high temperature or in the presence of impurities. These are called semiconductors. Such as silicon and germanium.

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