  Using quasi-time dependent semi-classical transport theory in RTA, we
obtained coupled current equations in the presence of time varying field and
based on general scattering mechanism $\tau \propto \mathcal{E}^{\beta}$. We
find that close to the Dirac point, the characteristic exponent $\beta = +2$
corresponds to acoustic phonon scattering. $\beta = +1$ long-range Coulomb
scattering mechanism. $\beta = -1$ is short-range delta potential scattering in
which the conductivity is constant of temperature. The $\beta = 0$ case is
ballistic limit. In the low energy dynamics of Dirac electrons in graphene, the
effect of the time-dependent electric field is to alter just the electron
charge by $e \to e(1 + (\Omega \tau)^2)$ making electronic conductivity
non-linear. The effect of magnetic filed is also considered.
