Half value layer refers to: (A) The rate at which an X-ray photon transfer its energy to irradiated matter, (B) The thickness of a substance required to reduce the number of X-ray photons by half, (C) The time taken for X-ray photons to travel half the distance from the source to the object, (D) The heel-effect seen when the anode is placed at an angle to the electron stream in the X-ray cathode tube
Answer is B. None