Question

what is the average energy of the x - ray beam called?
beam intensity
beam quality
beam quantity
beam velocity

Explanation:

Beam quality refers to the average energy of an x - ray beam. Beam intensity is related to the number of x - ray photons, beam quantity is also about the number of photons, and beam velocity is the speed of the x - ray beam which is constant (speed of light in vacuum).

Answer:

Beam quality