Question

name the scientist who discovered the electrons are present in an atom discrete orbits

Answer 1

neils bohr founded that

Answer 2

It was Neils Bohr.
"In 1913 as Rutherford's post-doctoral student, Niels Bohr proposed a new model of the atom, wherein electrons orbited the nucleus with classical periods, but were only permitted to have discrete values of angular momentum, quantized in unitsh/2π."