Electromagnetic interactions on light nuclei

In this contribution I will discuss the experimental results obtained for the two- and three-nucleon elastic form-factors. These observables have been recently studied up to momentum transfers of the order of 1 (GeV/c)2. The data obtained permit now a very careful discussion of the present status of the theory in this momentum transfer region. For instance it has been found that the purely nucleonic contribution is by far unable to explain neither the charge nor the magnetic experimental form factors. The few-nucleon form-factors thus provide us with one of the most convincing evidences for the importance of the meson exchange currents (MEC) in the electromagnetic processes. For most of the processes described below the contribution of MEC is large and significantly improves the agreement between theory and experiment. Still, the situation is not yet perfect; other degrees of freedom such as three-body forces, relativistic effects or quark clusters are likely to contribute. Contrary to MEC, the relative importance of each of these effects is not settled yet. In the following, the present achievements and limitations in the understanding of the few-nucleon form factors will be reported