  We consider a modified gravity theory, $f(R)=R+\alpha R^n-\frac{\mu^4}{R^m}$,
in the metric formulation and analyze the contribution of electromagnetic field
on the range of dynamical instability of a star filled with anisotropic matter.
The collapse equation is developed by applying conservation on anisotropic
matter, Maxwell source and dark source terms arising due to $f(R)$ gravity.
Specific perturbation scheme is implemented and it is observed that the
inclusion of Maxwell source slows down the collapse and makes system more
stable in Newtonian regime. Also, we make comparison of our results with the
existing literature.
