Final answer:
The net electric flux through a closed surface can be determined by calculating the net number of electric field lines passing through the surface. In this case, with 55.3 million excess electrons inside the closed surface, the net electric flux will be negative. However, the exact value cannot be determined without knowing the shape or size of the surface.
Step-by-step explanation:
The net electric flux through a closed surface can be calculated by determining the net number of electric field lines passing through the surface. In this case, we are given that there are 55.3 million excess electrons inside the closed surface.
Excess electrons have a negative charge, so they will create an electric field that points inward. Since the electric flux is defined as the number of field lines passing through a surface, the net electric flux through the surface will be negative. However, without knowing the shape or size of the surface, it is not possible to calculate the exact value of the net electric flux.