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Dear sir,please give me the answer of this question:- \" What is contact potential?\"
Administrator
on 2010-09-27 09:30:00Contact potential difference An electrostatic potential that exists between samples of two dissimilar electrically conductive materials (metals or semiconductors with different electron work functions) that have been brought into thermal equilibrium with each other, usually through a physical contact. Although normally measured between two surfaces which are not in contact, this potential is called the contact potential difference. Initially it is expected that mobile charge carriers (electrons or holes) will migrate from one sample to the other. If there is a net flow of electrons from material A to material B , material B will become negatively charged and material A will become positively charged, assuming that they were originally neutral. This process is self limiting because a potential difference between the two samples will develop due to the charge separation and will grow to a value sufficient to stop further motion of the electrons from A to B.
Aniket
on 2010-10-04 09:30:00Dear sir, you told here that \"If there is a net flow of electrons from material A to material B , material B will become negatively charged and material A will become positively charged, assuming that they were originally neutral.\" But, why we assume that they are originally neutral? How can we assume it??