Charging Process and Coulomb’s Law
Abstract This exercise is done to examine the interactions between charged systems. Several methods were used to observe the phenomena of charging by friction, electric conduction and induction. The experiments done were also associated with Coulomb’s Law which states the effect of distance and magnitude of charges on the force exerted. However, no numerical data were gathered in the experiment. The results of the experiments showed that the interactions between charged materials depend on the charge, either positive or negative. (insert conclusion)
I.
Introduction
A body is said to be electrically neutral if it contains the same number of protons and electrons. However, this body could have a ‘charge imbalance’ where there can be more protons than electrons in the body or the other way around. The body is to undergo charging where where it would gain a net charge (positive or negative) by placing it near or in contact with an electrically charged body. Three methods of charging are to be used in this experiment: charging by friction, charging by conduction and charging by induction. For bodies with charges at rest, the force exerted by the bodies on each other can be d etermined using the concept of Coulomb’s Law. This law states that the forces that the two point charges exert on each other are proportional to each charge, thus, proportional to the product of the magnitude of the t he two charges. T his paper discusses the different methods of charging an electrically neutral body and describes qualitatively the forces present between charged bodies. The objectives of this laboratory exercise are to determine the two kinds of charge and their properties, to examine the different processes of charging a neutral body, and to identify the interactions between charged systems.
II. A.
Methodology Rubbing of Rods The materials used in the experiment are tissue paper, plastic rod and metal rod. Bits of tissue papers were prepared and placed on the table. The plastic rod was rubbed with tissue paper and positioned near the tissue bits and observations were recorded. The process was repeated but using a metal rod and observations were documented again.
B. Hanging Plastic Sheets
Two plastic sheets and tissue paper were used in this experiment. The two plastic sheets were held close to each other with their surface facing each other and observations were recorded. Then, the plastic sheets were vigorously rubbed with the tissue paper and held again close to each other with the rubbed area facing each other. Observations were noted.
C. Tissue Bits
D.
Plastic sheet, tissue paper and tissue bits were used to perform the experiment. The bits of tissue papers were prepared and positioned on the table and a plastic sheet was placed on top of the bits. The process was repeated but instead of a plain plastic sheet, a plastic sheet rubbed with a tissue paper was used. It was ensured that the rubbed surface was facing the bits. The process with the rubbed plastic sheet was repeated but while the rubbed plastic sheet was on top of the tissue bits, the rubbed area was touched. Observations were recorded for the different processes.
Electroscope A plastic sheet was placed near the metal knob of the electroscope and observed. Then, the plastic sheet was rubbed with a tissue paper and slowly positioned near the metal knob. The foils were observed while the plastic sheet was moved closer to the metal knob. The process was repeated but this time, the rubbed surface touched the metal knob. Observations were recorded.
E.
Van de Graaff As the tissue pompoms were already in the spherical dome of the Van de Graaff generator, the only thing that had to do was rotate the crank handle vigorously. It was also made sure that the discharging metal ball was not in contact with the spherical dome of the generator. Observations were observed.
III. IV. V.
Results and Discussion Conclusion References
th
[1] R.A. Freedman and H.D. Young, University Physics with Modern Physics: 13 Edition, Chapter 21, Addison-Wesley, San Francisco, CA, 2012.
