Methods Of Charging

There are three methods of charging a body....
(i)Friction  (ii) Conduction    (iii) Induction

CHARGING FROM FRICTION : When two bodies are rubbed with each other one may loose electron and other may gain. The loosing body aquire +ve charge while the gaining body aquire equal and oppsite  -ve charge.As shown in the figure we can see that after rubbing rubber rod with fur..rubber aquire negative charge and fur aquire positive charge..









CHARGING FROM CONDUCTION:  When a charged body is brought in direct contact with an uncharged body, the charge will flow from chaged body to uncharged body as shown in figure. this method is called conduction








CHARGING FROM INDUCTION: In this a body is charged by bringing a charged body near to it without touching and earthing the other end...this can be explained in following three steps..

  Step (a) - in first step we bring a -ve charged rod near a conducting sphere..the -ve charge attract +ve charge towards itself and repell -ve charge in the sphere.

Step (b) - then the other end of sphere is earthed without moving the rod away from the sphere so that -ve charge flow to the earth.

Step(c) - after that slowly move the rod away from the sphere .

Step (d)- when you move the rod away from the sphere the +ve charge will spread..and the sphere is chaged by induction.

NOTE : the sphere is kept over an insulator and the rod is hold with an insulatin end so that charge will not flow to earth.

Types Of Electric Charges

About a century ago Charles Du Fay of France discovered that , there are two types of charges (i) positive charge & (ii) negative charge.

Benjamin Franklin (1706-1790)  an american scientist said that the charge developed on a glass rod when rubbed with silk is called positive charge & the charge developed on a plastic rod when rubbed with wool is called negative charge.....this convention consist a fact that when two equal and opposite charge are brought in contact with each other will cancel each other hence the chage on the electron is neutral...and this convention is taken as the present day convention.

FUNDAMENTAL LAW OF CHARGE: like charge repell each other & unlike charge attract each other , this property of charge is known as fundamental law of charge

Electrostatic

Electrostatic is defined as the study of electric charge at rest (as its name indicates electro reffers to electric charge and static means stable or at rest)

Following are some application of electrostatic

• it is used in xerox copying machine
• in chimneys to collect flyash
• in electrostatic loudspeaker