Final answer:
A fluorescent screen or an image intensifier is the device that converts X-ray energy into visible light for medical imaging and diagnostics.
Step-by-step explanation:
The device that transfers X-ray energy into visible light is called a fluorescent screen or an image intensifier. In medical imaging, this conversion is crucial as it turns the X-rays, which cannot be seen by the open eye, into a visible image that can be interpreted by medical professionals.
As X-rays are a form of high-energy electromagnetic radiation with short wavelengths, they are capable of penetrating solids such as the human body and ionizing gases. However, when they strike the fluorescent material on the screen, their energy is converted into visible light, which creates an image of the body's interior, allowing doctors to diagnose various conditions.