  In this paper, we study the effect of conversion of super-light sterile
neutrino (SLSN) to electron neutrino in matter like that of the Earth. In the
Sun the resonance conversion between SLSN and electron neutrino via the neutral
current is suppressed due to the smallness of neutron number. On the other
hand, neutron number density can play an important role in the Earth, making
the scenario of SLSN quite interesting. The effect of CP-violating phases on
active-SLSN oscillations is also discussed. Reactor neutrino experiments with
medium or short baseline may probe the scenario of SLSN.
