The correct answer is decreases/ decreases.
As a proton is a positively charged particle, it experiences the force against the electric field, directed from point 2 to 1 , which is constant, given by,
F = e×E, right to left. When a proton is moved in such a way from point 1 to point 2, work done is against the force & the potential energy increases U = F×d = e×E×d.
But an electron is negatively charged, with the same value, so that force experienced is along the field. Thus work is done by the field itself & potential energy decreases. It is similar to a body which falls under gravity.
Hence the option decreases/ decreases is correct.
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