  Photodisintegration and radiative capture in the N2H, N3H, N3He, 2H2H, 2H3He,
2H4He, 3He3H, 4He3H, and 4He3He channels are studied on the basis of the
corresponding two-cluster potential models. The astrophysical S factors at low
energies are calculated. It is shown that various electromagnetic
characteristics of light nuclei, including the Coulomb form factors at momenta
of up to 4 F-1 can be studied using a single set of intercluster interactions
containing forbidden states and consistent with the phase shifts of the cluster
low-energy elastic scattering. The calculated inelastic form factors have a
second maximum at 3-4 F-1, although it is lower than the experimental one. The
orbital states are classified for the lightest cluster systems, and the phase
shifts and intercluster potentials are separated on the basis of Young orbital
schemes.
  It is first part of the review. Other parts will be published later.
