<prompt> An increase in kVp increases the :Number of photons generatedTheir mean energyTheir maximal energyAll of the above  <response>: Increasing the kVp of an x-ray machine increases:The number of photons generated.The mean energy of the photons.The maximal energy of the photons.Ref:Ref: Oral Radiology, Principles and Interpretation Stuart C. White, Michael J. Pharoah - 7th ed - pg - 10 