Answer: A gamma ray has most energetic photons in the electromagnetic spectrum and also have the shortest wavelength.
Explanation:
Gamma ray is the packet of electromagnetic energy/photons emitted from excited nucleus of some radionuclide as a result of radioactive decay.
Gamma rays photons have energy greater than 100keV which account for the high penetrating power than that of X-ray. Gamma ray can penetrate various materials including human body, but a denser object like 'lead' can be used to slow or stop gamma rays.
X-ray wavelength are longer than the Gamma ray. X-ray energies range from 100eV to 200keV,but that of Gamma ray is higher which is above 100keV.
