Final answer:
Lead is used as the added filter material in x-ray tubes due to its high electron density and ability to absorb ionizing radiation more effectively, offering better protection and reducing the range of radiation.
Step-by-step explanation:
The material used as the added filter material in x-ray tubes plays a crucial role in protecting patients and technicians from excessive radiation exposure. Lead is known for its high density and the capability to absorb ionizing radiation effectively due to its densely packed electrons. This makes lead an excellent choice for radiation shielding. For example, in x-ray tubes, a lead apron is often used to protect certain body parts during imaging, and the x-ray tube itself is surrounded by lead shielding to limit exposure to unintended areas. The added filter material in x-ray tubes influences the range of radiation, as denser materials with higher electron density, like lead, reduce the range of radiation more effectively than materials with lower densities.