Charging by induction

PHYSICS

1. (Session : 2013 – 14)
Submitted by :
Himanshi
CLASS – XII
ROLL NO. ……….

2. CERTIFICATE
This is to certify that Himanshi has completed
this project “Charging by Induction” under
my supervision and completed to my total
satisfaction.
Mr. Sudhir Mishra
Physics Teacher

3. ACKNOWLEDGEMEN
T
I am very thankful to my teacher Mr. Sudhir
Mishra for providing me an opportunity to do
this Project. I would like to express my
gratefulness to all those who helped me in
completion of the project report.

4. INDEX
I.Material Required.
II.Objectives.
III.Aim.
IV.Introduction.
V.Procedures.
VI.Results.
VII.Precaution.

5. Material Required
Two Pith Balls.
Two Insulating Stands.
Electrified Glass Rod.
Objectives
To charge a pith ball by the method of
charging by Induction.

6. Charging by Induction
Aim :
The main aim of this project is to investigate
the method of charging by induction.
Introduction :
When we touch a pith ball with an
electrified plastic rod, some of the negative
charges on the rod are transferred to the pith ball
& it also gets charged. Thus the pith ball is
charged by contact.
Procedure :
The main aim of this project is to investigate
the method of charging by induction.

7. Procedure :
(i)Bring two metal spheres A & B,
supported on insulating stand in contact
as shown in fig.
(ii)Bring a positively charged rod near one
of the sphere, say A taking care that it
does not touch the sphere. The free
electrons in the sphere are attracted
towards the rod. This leaves an excess of
positive charge on the rear surface of
sphere B. Both kind of charges are
bound in the metal spheres & cannot
escape. They, therefore, reside on the
surfaces as shown in negative charge &
right surface of sphere B, has an excess
of positive charge. However not all of
the sphere in the electron have
accumulated on the left surface of A.

8. As the negative charge starts building up at
the left surface of A, other electrons are
repelled by these in a short time, equilibrium
is reached under the action of force of
attraction of the rod & the force of repulsion
due to the accumulated charges.
Fig. 1.4 (b) shows the equilibrium situation.
The process is called induction of charge &
happens almost instantly. The accumulated
charges remain on the surface as shown, till
the glass rod is held near the sphere. If the
rod is removed, the charges are not acted by
any outside force & they redistribute to their
original neutral state.

9. (iii)Separate the spheres by small distance
while the glass rod is still held near
sphere A, as shown in fig. 1 (c). The two
spheres are found to be oppositely
charged & attract each other
(iv)Remove the rod, the charges on the
sphere rearrange themselves as shown in
fig. 1 (d). Now, separate the spheres
quite apart. The charges on the sphere
get uniformly distributed over them as
shown in fig. 1(e)
In this process, the metal spheres will
each be equal and oppositely charged. This is
charging by Induction.

10. Result
The pith balls are successfully charged by the
method of induction.
Precautions :
Pith ball should be supported on insulating
stands properly and carefully.
The rod should be brought near the spheres
taking care that it should not touch the
sphere.