Free Electrons | Methods of Charging

KNOW | FREE ELECTRONS

You have learnt that there exist two charge particles in every material and electron is one of them having a negative charge.

Now what are free electrons?

We know that every atom consist electrons in it but, can we pull them out of its parent atom? The answer is yes, we can pull out the electrons from their parent atom by giving energies to them, the amount of which depends upon the shell number from they are pulling out and this process is known as ionization .

in metals The Outermost electrons experiences Less Effective Nuclear Charge and less attractive force, so these electrons of Metals are Almost Free to Move. and We say these Free Electrons                                                                                                                        

 

After knowing about free electrons you can easily understand the following methods of charging a body.

Methods of Charging 

 

Charging by induction :– 

You can simply guess by the title that there must be the process of induction.

Yes, in this process there is induction of charge by an already charged body take place without actual contact.

Let take an example to understand well.                                                                                                                                                                  

Suppose we have a metallic sphere with an insulating stand.         Now bring a positively charged rod near the sphere, but don't touch   with it.                                                                                                            

                                                                                    

Some of the electrons of the sphere will attracted by the rod as shown in the figure 1(a).                                                                        Now there is a formation of a small positive charge in the opposite side of the sphere.

Now connect one side of a conducting wire with the positively charged side of the sphere and second side of the wire with an another metallic sphere.

Some of the electrons will flow from the second metallic sphere to the first metallic sphere through the conducting wire as shown in the figure 1(c). After bringing out the wire and the rod we have two oppositely charged metallic sphere.

This process of charging a body is known as charging by induction.                                                                                             You can check the presence of charge on them by bringing a rubbed paper stripe close to them one by one you will see that first sphere will attract it and second one will repel it.                                                                                                                                                                                                                                                                         Charging by conduction:–

Now we are going to talk about the third method of charging a body which is charging by conduction or contact. 

You may notice that in the previous section we talk about the charging of a body without any actual contact but in this section we will discuss about charging by contact.                                                   

Let see, we have a charged metallic sphere and a small neutral metallic sphere fig.2(a). 

Now bring the small one which is neutral in contact with the charged sphere and after 2–3 seconds bring it as shown in the fig.2(b). out now our small sphere is charged.

 You can check the presence of charge in it using a small rubber paper stripe. 

This simple method of charging is known as charging by conduction or charging by contact.

Author-   ANUJ 

Email - anuj2005gupta@gmail.com

Formatted By- THINKit Team
Last Updated-  20 September 2020 at  11:33 hrs IST