Abstarct: The study of nucleon structure always has been highly regarded. Useful information from the form factors, internal structure and the constituent particle of nucleons is obtained by studying the elastic, inelastic and deep inelastic scattering cross-section. In classical electrodynamics, we attribute the electrical repulsion of two electrons, say, to the electric field surrounding them; each electron contributes to the field, and each one responds to the field. But in quantum field theory, the electric field is quantized (in the form of photons), and we may picture the interaction as consisting of a stream of photons passing back and forth between the two charges, each electron continually emitting them and continually absorbing them. In the case of electrodynamics, the mediator is the photon. The quantum theory of electrodynamics was perfected by Tomonaga, Feynman, and Schwinger in the 1940s. Internal lines (those which begin and end within the diagram) represent particles that are not observed-indeed, that cannot be observed without entirely changing the process. We call them “virtual” particles. Only the external lines (those which enter or leave the diagram) represent “real” (observable) particles. The external lines, then, tell you what physical process is upcoming; the internal lines describe the mechanism involved. When you want to analyze a certain physical process. First, you draw all the diagrams that have the appropriate external lines (the one with two vertices, all the ones with four vertices, and so on), then you evaluate the contribution of each diagram, using the Feynman rules, and add it all up. The sum total of all Feynman diagrams with the given external lines represents the actual physical process. In this thesis, we have tried to study the nucleon and its resonances with a new approach. This means that in the electron-proton scattering, the interaction of photons with the current of the constituent quarks is studied. We study the electromagnetic interaction between the quark current and the electromagnetic field of photons and show that the Hamiltonian interaction consists of the spin transfer operators and a momentum transfer operator, and since the separate study of the effect of these two operators on the interaction of electromagnetic is a complex work, the quantum number of a helicity, which is highly dependent on the total momentum, has been introduced. The changes in this quantum number by the transition to different resonance modes are obtained. Therefore, the relationship between the helicity amplitudes and the electromagnetic form factors is calculated.