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Electricity

1. Electricity:-

The energy that is produced either due to flow of electrons or due to unequal number of electrons in an atom is called electricity or electrical energy.

Electrical energy is divided into two types.

They are: -

(i) Static electricity.

&

(ii) Current Electricity.

(i) Static Electricity: -

The electrical energy that is produced due to unequal number of electrons in an atom is called static electricity.

This type of energy is produced in an insulating body. Such type energy cannotflow through the external conducting wires.

(ii) Current Electricity: -

The electrical energy that is produced due to flow of electrons through the conducting wire is called current electricity.

This type of energy is produced in a conducting body so it can flow through the external conducting wire.

2. Differences between static and current electricity:-

Some differences between static and current electricity are as follows: -

Static electricity Current electricity
* It is produced due to unequal number of electrons in an atom. * It is produced due to flow of electrons in the conducting wire.
* It does not flow through the external conducting wire. * It flows through external conducting wire.
* It is produced in an insulating body. * It is produced in a conducting body.

3. Sources of Electricity: -

Those devices that can produce electrical energy from them are called sources of electrical energy.

For Example: -

Cell

Dynamo

Generator.etc.

4. Electrodes: -

Two metal plates used in the cell are called electrodes.

Between two electrodes, one is positive terminal and next is negative terminal.

5. Electrolyte:-

A liquid that is used in the cell is called electrolyte.

It decomposes into ions on its decomposition.

6. Differences between electrodes and electrolyte: -

Some differences between electrodes and electrolyte are as follows.

Electrodes Electrolyte
* Electrodes are in solid state. * Electrolyte is in liquid in state.
* It does not decompose in ions. * It undergoes in ions.

7. Anode:-

The positive terminal of the cell is called anode.

8. Cathode:-

The negative terminal of the cell is called cathode.

9. Differences between anode and cathode: -

Some differences between anode and cathode are as follows.

Anode Cathode
* It is the positive terminal of the cell. * It is the negative terminal of the cell.
* Negative ions migrate towards it. * Positive ions migrate towards it.

10. Cell:-

The device that converts chemical energy into electrical energy is called cell.

There are two types of cells.

They are:-

(i) Simple cell

&

(ii) Dry cell.

(A) Simple Cell:-

A source of electricity that consists of copper and Zinc plates as electrodes and dilute sulphuric acid is used as an electrolyte is called simple cell.

It is called simple cell because it simple in structure.

Construction:-

This cell consists of a glass or plastic vessel called voltameter. It contains water with few drops of sulphuric acid which is called an

electrolyte. Two metal plates (electrodes) copper and zinc are kept in the vessel containing acid water. Here copper plate behaves as

positive electrode and zincplate behave as negative electrode. When these two electrodes are connected with a bulb withthe help of

conductingwire then chemical reaction occurs there as result electrons flows through the circuit and bulb glows as shown in the figure.

image-20200906173900010

Figure:- Simple Cell

(B) Dry Cell:-

A source of electricity that consists of carbon rod with brass cap as electrodes and paste of ammonium chlorideis used as an electrolyte is called dry cell.

It produces the potential differences of 1.5 volts.

Construction:-

This cell consists of a zinc container as a negative terminal and carbon rod with a brass cap as positive terminal.This cell does not contain any liquid in it but a paste of ammonium chloride (NH4Cl) is used as an electrolyte. A mixture of carbon powder and manganese dioxide (MnO2) is alsoused inside the dry cell. When two terminals of cell are connected with the load then chemical reaction takes place as a result flow of electrons takes place then bulb glows.

image-20200906173922263

Figure:- Dry Cell

11. Advantages of Dry cell over Simple cell: -

Some advantages of dry cell over simple cell as follows: -

· It does not contain any complete liquid as an electrolyte like simple cell so it is easy to carry from one place to another.

· It does not consist brittle vessel like simple cell so there is no chance of breaking.

· It produces potential difference of 1.5 Volt which is more than simple cell.

· It does no have any defects like polarization and local action as simple cell has.

12. Differences between Simple Cell and Dry Cell:-

Some differences between simple cell and dry cell are as follows.

Simple Cell Dry Cell
* Dilute sulphuric acid is used as an electrolyte. * Paste form of ammonium chloride is used as an electrolyte.
* It produces the potential difference of 1.08 Volt. * It produces the potential difference of 1.5 volt.
* It has two defects. * It has no defects.
* It is difficult to carry. * It is easy to carry.

 

13. Dynamo or Generator:-

Dynamo or generator is a device that converts mechanical energy in to electrical energy.

i.e.

Mechanical Energy Dynamo or Generator Electrical Energy

Dynamo produces small magnitude of current so it is used in the bicycle but generator produces more magnitude of current so it is used in the factories.

Both dynamo and generator contain magnet and coil inside it.

14. Electric Circuit:-

A conducting path through which electric current passes from source to the load is called electric circuit.

There are three types of circuits.

They are:-

(i) Open Circuit

(ii) Closed Circuit

&

(iii) Short Circuit.

(i) Open Circuit:-

The circuit in which there are some disconnections somewhere so current does not flow from source to the load as a result load does not perform its work is called open circuit.

The diagram of open circuit has given.

image-20200906173943134

Figure:- Open Circuit

(ii) ClosedCircuit:-

The circuit in which there -is no disconnection anywhere so current flows from source to the load as a result load performs its work is called open circuit.

The diagram of close circuit has given.

image-20200906173959838

Figure:- Closed Circuit

(iii) Short Circuit:-

The circuit in which positive and negative terminal of a load or source are connected directly with a conducting wire is called short circuit.

This circuit is danger to touch because excessive current flows through it.

image-20200906174011607

Figure:- Short Circuit

 

15. Combination of Cell: -

When two or more than cells are connected in a group, this is called combination of cells.

· Battery:-

Battery is a group of two or more than cells.

Mainly there are two types of combinations of cells.

They are:-

(i) Series combination of cells

&

(ii) Parallel combination of cells.

(i) Series combination of cells:-

The combination of cells in which positive terminal of one cell is connected to negative terminal of second cell, positive terminal of

second cell is connected to negative terminal of third cell and so on is called series combination of cell.

image-20200906174027428

Figure:- Series Combination of Cells

Advantages of Series Combination:-

Some advantages of series combination of cell are as follows:-

· The speed of doing work by the load increases as the number of cells increases.

For Example:-

The brightness of the bulb increases as the number of cells increases in the circuit.

· Magnitude of potential differences in the circuit increases as the number of cells are increased in the circuit as a result the magnitude of current also increases.

Disadvantages of Series Combination:-

Some disadvantage of series combination of cells in the circuit are as follows:-

· The working hour of the load does not increase even the number of cells are increased in the circuit.

For Example:-

The duration of glowing bulb does not increase even the number of cells are increased in the circuit.

· If any one cell in the circuit is damaged, then the load does not work even other cells are good.

(ii) Parallel Combination of Cells: -

The combination of cells in which all positive terminals of the cells are connected to one point and all negative terminals are connected to another point is called parallel combination of cell.

image-20200906174039581

Figure: - Parallel Combination of cells.

Advantages of Parallel Combination: -

Some advantages of parallel combination of cells are as follows: -

· The working hour of the load increases as the number of cells in the circuit increases.

For Example: -

If one cell can glow a bulb for 1 hour, then it glows for 2 hours if two cells are parallelly added in the circuit.

· If anyone cell in the circuit is damaged, then also load performs the function.

Disadvantage of Parallel Combination:-

Some disadvantages of parallel combination cells are as follows:-

· The working speed of load does not increase even the number of cells are added in the circuit.

For Example: -

The brightness of the bulb does not increase even the number of cells are added in the circuit.

· The amount of potential differences can not be increased in the circuit by the addition of number of cells in the circuit.

16. Differences between Series combination and Parallel combination of Cell:-

Some differences between series combination and parallel combination of cell are as follows.

Series Combination of cells Parallel combination of cells.
* Positive terminal of one cell is connected with the negative terminal of another cell. * All positive terminals are connected at one point and all negative terminal are connected to another point.
* Brightness of bulb increases as the number of cells are added. * Brightness of the bulb does not increase as the number of cells increases.
* Time period of glowing bulb does not increase as the number of cells are increased in the circuit. * Time period of the bulb increases as the number of cells are increased in the circuit.
* If one cell is damaged, current does not flow through the circuit * If one cell is damaged, current flows through the circuit.

The End

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This content is contributed by:

Dipak Dangi