Notes, Exercises, Videos, Tests and Things to Remember on Current Electricity
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Every material is made up of an atom and every atom is made up of two types of charged particles. They are protons and electrons. Protons are positively charged and electrons are negatively charged. Different metals like copper, iron, aluminium etc consist of a large number of free electrons. When this free electron flows continuously in a certain direction, electric current is produced. Therefore, current electricity is the continuous flow of electrons. Current electricity is a form of energy. It is used for various purpose. It can be easily converted into heat energy, light energy, sound energy, magnetic energy, etc.
Electricity has become one of the important part of human life. It is very difficult to live without electricity. We use various types of electrical appliances such as computer, television, radio, mobile, refrigerator, calculator, watch etc. These appliances make our life easier and comfortable to live. To run all these appliances, we need electrical energy. Electrical energy is also very important to run various industries, factories, transportation systems and many other important things. The devices from which we obtain electricity are called sources of electricity. The three major sources of electricity areas follow,
An electric circuit is a path through which an electron from current source or voltage flows. It is also the path made by connecting a cell, a conducting wire and a bulb. There are various things that are required for making an electric circuit which are discussed below,
Open circuit and Closed circuit
An open circuit is a type of circuit in which the switch is made 'OFF' and the bulb does not glow. During this condition, the current cannot flow through the wire. So, the load cannot function when the circuit is opened. Talking about the close circuit, it a type of circuit in which the switch is made 'ON'. In a closed circuit, the bulb glows as the current flows through the circuit continuously.
Symbols used in Circuit Diagrams
While drawing circuit diagrams, we cannot draw all the components used in electric circuit. It is very difficult and takes lots of time to draw the various components like battery, wire, voltmeter,galvanometer etc. So, to save time and for easy, various symbols representing various components used in electric circuit are used. Some of the symbols that are used moslty in an electric circuit are given below,
|1.||Cell||Source of electric current|
|2.||Bulb||To produce light|
|3.||Wire||To make conducting path|
|4.||Load or Resistance||To convert electrical energy into other forms of energy like heat and light|
|5.||Galvanometer||To detect the current|
|6.||Switch||To put the current on or off in the circuit|
|7.||Battery||Source of electric current|
|8.||Voltmeter||To measure the voltage|
|9.||Ammeter||To measure the current|
Cell is also one of the sources of electricity. It produces electric current. We use cell for various purpose. Sometimes we need low voltage and sometimes we need high voltage. To have different voltage, we should connect the cells in different ways. Mainly there are two ways of combination of the cells which are discussed below,
If the positive terminal of the first cell is connected to the negative terminal of the second cell and positive terminal of the second cell with the negative terminal of the third cell and so on is called a series combination of the cell.
If the positive terminal of all cells are connected to a common point and all the negative terminals are connected to another common point in a circuit, the combination of cells is called parallel combination.
The things required for making electric circuit are given below,
There are two types electric circuit. They are discussed below,
The differences between static electricity and current electricity are given below in table,
|Static electricity||Current electricity|
|The electricity in which electric charges remain at rest (or stationary) is called electricity.||The electricity in which electric charges remain at continuous motion is called current electricity.|
|Static electricity cannot be transferred from one point to another through a conductor.||Current electricity can be transferred from one point to another through a conductor.|
The differences between series combination and parallel combination of cells are given below,
|Series combinations of cell||Parallel combinations of cell|
|The combination of cells in which positive terminal of the first cell is connected to the negative terminal of the second cell, positive terminal of the second cell is connected to negative terminal of the third cell and so on is called series combination of cell.||The combination of cells in which positive terminal of all cell are connected to a common point and negative terminals of the same cells are connected to another common point is called parallel combination of cells.|
|In series combination, the total voltage is equal to the sum of individual voltage.||In parallel combination, the total voltage is equal to the voltage of each cell.|
When the switch is made 'OFF', then the circuit is known as