Electrostatics Lab Report

   Akhil Kumar, Phy 122- L02                                  

Submitted to: Kevin Douglas

                                                 ELECTROSTATICS

Aim: The of this lab is to find the aspects of electric charge and calculate the value of Q, and check the amount of charge present on the pith ball.

Abstract: This experiment is combination of 5 exercises and all these are dealing with the attraction of static electricity. Each part provide specific example to how static electricity loses and gains conductivity. This report will explain the results of each if the part that were done in this lab.

Overview and Theory: Two kinds of charges are found in the world i.e. negative and positive charges. Like charges are repel each other and opposite attract each other. The positive charge means an object have more protons than electron and the negative means having more electrons than protons. Charges are known to come in multiples of an indivisible unit of charge. They are represents by the letter e. A proton has a charge of +e and the electron has a charge of –e. one of the most important equation is putting “charge is quantized” (q=n e), where q is the symbol that represents a charge. While the n is a positive or negative integer, and e represents 1.60 x 10-19 Coulombs.

Most things are electrically

neutral. They usually have both positive and negative charges. Metal are known as good

conductors of electrical charges. While rubbers, plastics and wood are not. These are

known as insulators. Charges do not flow easily throughout insulators. Rubber coating is

usually used around copper wires due to the fact it insulates electricity really well. One of

the most evident events is charging by friction, this was used throughout the experiment.

Much like the plastic ruler, the rabbit fur and that the aluminum exercise, it displayed

how electrons have a tendency to be transferred from one material to another.

Charging

by conduction is another example. This is very useful when charging metals and other

conductors. Charges are transferred between the object and the conductor. Charging the

conductor with the same sign as the charge on the object.

And the other good example is charging by polarization of objects in this by bringing a charged object near to neutral, this slight difference of charge makes one side of the body somewhat positive and the opposite side somewhat negative.

Procedure:

1. Charging by Friction

In this part two rods were used i.e. grey rod and white rod. When grey rod rubbed with wool cloth and white rod rubbed with green cloth.

When Grey rod rubbed with wool cloth and tested in charge measurement sensor it showed negative charge i.e. -78.16 nC

That is number of electrons present on the rod was

e = elementary charge = 1.6 ×10-19 C

electron charge is –e

so  -1 nC =   - 10-9 C/ -1.6 × 10-19 Ce-1

                       = 6.25 ×109 electrons

therefore for -78.16 nC = -78.16 ×10-9 C[pic 1][pic 2]

                                                                    -1.6 × 10-19 Ce-1

        = 4.89 × 1011 electrons

initially the rod was neutral but after friction the rod gain 4.89 × 1011 electrons.

-When white rod tested in sensor +65.72 nC charge found on it

i.e. the number of electron present on the rod =  +65.72 × 10-9 C[pic 3]

                                                                                        - 1.6 X 10-19 Ce-1

               = - 4.12 × 1011 electrons

therefore the rod loose -4.12 ×1011 electrons 

1. Charging by Induction

In this part we placed a charge pith ball inside the can and tested it at different depths we found some unexpected results i.e.

• ¼ way down from the top

• the charge was -2.87 nC

• ½ way down from the top

-     the charge was -1.20 nC

• ¾ way down from the top

• the charge was -2.18 nC

• very close to the bottom of the can but not touching

• the charge was -2.30 nC

The charge should be same at all the position but it varies it may be because of charge loss in the room or may be the ball touch to the can.

1. Charging by Conduction

In this part the charge transfers to the can. i.e. charged rod touched to the can and the charge transfer to the can this is called charging by conduction.

...