About VAN DE GRAAFF GENRATOR

1. ALL INDIA SENIOR SCHOOL
CERTIFCATE EXAMINATION
(2017-2018)
DIVINE CHILD SCHOOL
AMIPURA , MEHSANA
BY :RAHIL PARSANA
ROLL NO. :
CLASS : XII SCIENCE A
YEAR : 2017-2018
PHYSICS PROJECT ON
“VAN DE GRAAFF GENRATOR”

3. Acknowledgement
I acknowledge that the great timely and voluntarily help
guidance from the following personalities without which
the project could not be completed successfully.
First of all I wish to express my heartily thanks to the
school management , Anandi Mam and principal
Mr. K. M. Cherian to provide all sorts of helps to finish the
project perfectly. Then comes my physics teacher Mr.
KumarRajesh &Mr.PawanSingh , who proposed the topic
which I liked the most to work and were always with me
in every aspect of the project for the successful
transformation of the idea in the mind to real work as
project report.
RAHIL PARSANA

4. CERTIFICATE
THIS IS TO CERTIFY THAT THIS PROJECT ENTITLED “VAN DE-
GRAAFF GENERATOR” SUBMITTED TO MR. KUMAR RAJESH&MR.
PAWAN SINGH OFPHYSICS DEPARTMENT,DIVINE CHILDSCHOOL
(MEHSANA) AND WAS CARRIED OUT BY HIM UNDER GUIDANCE
AND SUPERVISION DURING THE ACEDEMIC YEAR 2017-2018.
MR. KUMAR RAJESH AND MR. PAWAN SINGH
(PHYSICS TEACHERS)
Mr. K. M. Cherian
( Principal )

5. DECLERATION
I do hereby declare that this project work has been
originally carried out by me under the guidance and
supervision of Mr. Kumar Rajesh & Mr. Pawan Singh
of DIVINE CHILD SCHOOL (MEHSANA)
DATE :
PLACE : DIVINE CHILD SCHOOL, MEHSANA
RAHIL PARSANA

6. CONTENTS
1. INTRODUCTION
2. PRINCIPLE
3. WORKING
4. CONSTRUCTION
5. DESCRIPTION
6. APPLICATION
7. BIBLIOGRAPHY

7. INTRODUCTION
A van de Graaff generator is an electrostatic generator
which uses a moving belt to accumulate electric charge
on a hollow metal globe on the top of an insulated
column, creating a very high electric potential. It produces
very high voltage, Direct current (DC) electricity at low
current levels. It was invented by American physicist
Robert J van de Graaffin 1929. The potential difference
achieved in modern van de Graaff generators can reach 5
Mega volt. It is used as a means of physical education in
electrostatics, larger ones are displayed in science
museums.

8. PRINCIPLE
Electrostatic generators such as the wimshurt machine,
the van de Graaff generator and the electrophorus, use
this principle, of electrostatic induction. Due to induction,
the electrostatic potential is constant at any point
throughout the conductor. Due to induction, attraction of
non conductive objects occur. Electrostatic Induction
must not be confused with electromagnetic induction.

9. HOW IT WORKS
There are 2 types of van de Graaff generators. This one
uses the triboelectric effect, in which certain materials
become charged by contact with other materials like
when you rub a balloon with your hair.
During operation, a motor and roller at the bottom
of the generator drive a rubber belt around a glass roller
at the top, which creates a negative charge on belt. A
metal brush transfers this charge to a soda can, which is
able to store a large amount of charge because it is both
hollow and a conductor. The belt meanwhile becomes
depleted of free electrons and needs to be replenished,
and so a second brush at the bottom pulls in charge from
whatever it’s connected to.

10. CONSTURCTION
1) Hollow Metal Sphere
2) Upper electrode
3) Upper Roller (Metal)
4) Side Of The Belt With Positive Charges
5) Opposite Side Of The Belt With Negative Charges
6) Lower Roller
7) Lower Electrode (Ground)
8) Spherical Device With Negative Charges, Used To Discharge The Main Sphere
9) Spark Produced By The Difference Of Potentials

11. DESCRIPTION
A simple Van de Graaff-generator consists of a belt of silk, or a
similar flexible dielectric material, running over two metal
pulleys, one of which is surrounded by a hollow metal sphere.(1)
Two electrodes, (2) and (7), in the form of comb-shaped rows of
sharp metal points, are positioned respectively near to the
bottom of the lower pulley and inside the sphere, over the
upper pulley. Comb (2) is connected to the sphere, and comb (7)
to the ground. A high DC potential (with respect to earth) is
applied to roller (6)

12. APPLICATION
 They are used where a very high voltage at very low current is
needed.
 The beam of these charged accelerated particles is used to
trigger the nuclear reaction .
 In medicine, such beams are used to treat cancer.
 Accelerated particle beams are used to break atoms for
various experiments in physics .

13. BIBLIOGRAPHY
 WWW.GOOGLE.COM
 WWW.WIKIPEDIA.COM
 PHYSICS NCERT TEXT BOOK