We present a multi-wavelength analysis of the merging rich cluster of galaxies Abell 2256 .
We have observed A2256 at 150 MHz using the Giant Metrewave Radio Telescope and successfully detected the diffuse radio halo and the relic emission over an extent \sim 1.2 Mpc ^ { 2 } .
Using this 150 MHz image and the images made using archival observations from the VLA ( 1369 MHz ) and the WSRT ( 350 MHz ) , we have produced spectral index images of the diffuse radio emission in A2256 .
These spectral index images show a distribution of flat spectral index ( S \propto \nu ^ { \alpha } , \alpha in the range -0.7 to -0.9 ) plasma in the NW of the cluster centre .
Regions showing steep spectral indices ( \alpha in the range -1.0 to -2.3 ) are toward the SE of the cluster centre .
These spectral indices indicate synchrotron life times for the relativistic plasmas in the range 0.08 - 0.4 Gyr .
We interpret this spectral behaviour as resulting from a merger event along the direction SE to NW within the last 0.5 Gyr or so .
A shock may be responsible for the NW relic in A2256 and the Mpc scale radio halo towards the SE is likely to be generated by the turbulence injected by mergers .
Furthermore , the diffuse radio emission shows spectral steepening toward lower frequencies .
This low frequency spectral steepening is consistent with a combination of spectra from two populations of relativistic electrons created at two epochs ( two mergers ) within the last \sim 0.5 Gyr .
Earlier interpretations of the X-ray and the optical data also suggested that there were two mergers in Abell 2256 in the last 0.5 Gyr , consistent with the current findings .
Also highlighted in this study is the futility of correlating the average temperatures of thermal gas and the average spectral indices of diffuse radio emission in respective clusters .