Finding the mass of digested DNA by electrophoresis - (May/23/2022 )

If I digest a 1ug 1000bp DNA fragment into 100bp and 900bp fragments and pass those 1ug fragments through an electrophoresis gel, will the ng masses of the resulting fragments also be distributed proportionally in the gel into a 100ng 100bp fragment and a 900ng 900bp fragment?

Yes.