Which one has highest energy neutron or photon?

Answer 1

Both of them can have a low or a high energy.

The question is essentially meaningless for the above reason, but let's try to answer it anyway.

Neutrons have an inherent energy equivalent to their mass (which is, for a subatomic particle, pretty substantial).

The energy of a photon can be pretty much any desired value. Low-energy photons have low frequencies; high-energy photons have high frequencies.

The energy equivalent of a neutron at rest is roughly equal to that of a photon with a frequency of 2.2 x 1023 Hz. This is an amazingly high frequency (way up in the gamma region of the spectrum, which starts at around 1019Hz), so it's rather likely that for any given photon/neutron pair, the neutron has a higher overall energy.

Gamma-ray bursts can contain photons with energies far higher than a neutron at rest, though. The neutron energy is around a GeV; gamma-ray bursts can have photons with energies in excess of 10 TeV, 10,000 times higher.

Answer 2

Neutrons have higher energy than photons. Neutrons are particles with rest mass, while photons are massless particles. The energy of a neutron is determined by its mass and velocity, whereas the energy of a photon is solely determined by its frequency.