Electron collision cross sections at low energies for all transitions between the n=1, 2, 3, 4 and 5 levels of atomic hydrogen

Collision strengths for all transitions among states up to the n=5 level are reported in the energy range below 1.96 Ryd. The R-matrix and no-exchange programs have been used for partial waves with L<or=9 and L>9 respectively. The results are analysed in detail highlighting the resonance structure. They are also compared with other results. The effective collision strengths obtained after averaging the collision strengths over a Maxwellian distribution of electron velocities are listed at temperatures below 50000 K. Though the results require an improvement especially in the intermediate energy region, nevertheless they are probably the best available for most of the transitions.