In this article, we analyzed the second law of thermodynamics applied to an electrically conducting incompressible water based nanofluid flow over a stretching sheet in the presence of thermal radiation and uniform heat generation/absorption both analytically and numerically. The basic boundary layer equations are non-linear PDEs which are converted into non-linear ODEs using scaling transformation.  The dimensionless governing equations for this investigation are solved analytically using hyper geometric function and numerically by the fourth order Runge Kutta method with shooting iteration technique. The effects of partial slip parameter with the nanoparticle volume fraction, magnetic parameter, radiation parameter, uniform heat generation/absorption parameter, suction parameter, dimensionless group parameter, Hartmann number and Reynolds number on the entropy generation are discussed  for various nanoparticles such as  Cu, Ag, Al₂O₃ and TiO₂. It is found that the entropy generation enhances with the increase of magnetic parameter and Hartmann number and decreases with slip parameter .