Charge

1. Charge, Lightning and Thunderstorms 1.Types of Charge 4.Lightning 2.Transfer of Charge 5.Thunderstorms 3.Earthings

2. charge The thing that "flows" in the current is the “charge” . A charge may refer to one of many different quantities ,such as the electric charge in electromagnetism Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field .

3. Types of Charges

4. Positive ,negative and neutral charge All matter in electricity is made of atoms , which contain electrons , protons and neutrons . An object with more protons than electrons is said to carry a positive charge. An object with more electrons than protons is said to carry a negative charge. A neutral charge is one that is made up of the same number of electrons and protons .

5. Transfer of charge There are three methods by which charges can be transferred to build up static electricity: charging by friction, by conduction, and by induction. Charging by Friction - When two uncharged objects rub together, some electrons from one object can move onto the other object. The object that gains electrons becomes negatively charged, and the object that loses electrons becomes positively charged. Charging by friction is the transfer of electrons from one uncharged object to another by rubbing.   Charging by Conduction - When a charged object touches another object, electrons can be transferred between the objects. Electrons transfer from the object that has the more negative charge to the one that has the more positive charge. For example, a positively charged object will gain electrons when it touches an uncharged object. Charging by conduction is the transfer of electrons from a charged object to another object by direct contact.

6. Transfer of Charge ( Continue ) Charging by induction - In charging by friction and by conduction, electrons are transferred when objects touch one another. In charging by induction, however, objects do not touch when the charges transfer. Charging by induction is the movement of electrons to one part of an object that is caused by the electric field of a second object. The electric field around the charged object attracts or repels electrons in the second object A device that can be used to test whether an object is carrying charge or not .This device is known as electroscope.

7. Earthing The process of transferring of charge from a charged object to the earth is called Earthing. Earthing is the process of creating an alternative path for the flow of fault/excessive currents safely into the ground

8. The primary purpose of earthing is to reduce the risk of serious electric shock from current leaking into uninsulated metal parts of an appliance, power tool, or other electrical devices. In a properly earthed system, such leaking/fault current is carried away harmlessly while tripping the fuse. Earthing also provides protection from large electrical disturbances like lightning strikes and power surges. It also aids in the dissipation of hazardous static electrical charges. Although most electrical systems have fuses or circuit breakers for protection against a fault current, the human body may be fatally electrocuted by a current of less than one ampere which is well below the point at which a fuse or breaker will operate. Earthing helps minimize such hazards from occurring. Why earhting happens ?

9. Thunderstorms A thunderstorm is a storm with lightning and thunder. Its produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail. A thunderstorm is also known as electrical storm, a lightning storm or a thundershower. Do’s and don’ts during a thunderstorm Outside Open vehicles are not safe . Open fields,tall trees shelters in park, elevated places do not protect us from lightning strokes. Carrying an umbrella is not at all good idea during thunderstorms. video

10. Outside If in a forest take shelter under shorter trees. If no shelter is available stay far from all trees. Stay away from poles or other metal objects. Do not lie on the ground. Inside the house During a thunderstorms contact with telephone cords, electrical wires and metal pipes should be avoided . It is safer to use mobile phones and cordless phones . Bathing should be avoided during thunderstorms to avoid contact with running water. Electrical appliances should be unplugged

11. Lightning Lightning is a bright flash of electricity produce by a thunderstorms. All thunderstorms produce lightning , which are very dangerous . Lightning is most common around the equatorial regions of the world ,although it can possibly strike anywhere,and it varies in appearances ,depending on atmospheric conditions. We have seen the electric spark on the pole when wire becomes loose. Lightning is also an electric spark but on a huge scale . Lightning is caused by the accumulation of the charges in the clouds.

12. Lightning safety During lightning and thunderstorms no open place is safe. Hearing thunder is an alert to rush to a safer place. After hearing the last thunder , wait for sometime before coming out of the safe place. FINDING A SAFE PLACE A house or a building is a safe place . If you are travelling by car or by bus you are safe inside with windows and doors of the vehicle shut.

13. Thank you