Final answer:
X-rays are the type of electromagnetic radiation that can penetrate soft tissue but are absorbed by harder tissue such as bone, making them suitable for medical imaging.
Step-by-step explanation:
The type of electromagnetic radiation that can penetrate soft tissue but not hard tissue like bone is referred to as X-rays. X-rays have wavelengths between 0.01 nanometer and 20 nanometers, allowing them to pass through soft tissues while the dense material of bones absorbs them effectively, resulting in the familiar images used in medical diagnostics. Unlike gamma rays which have even greater energy and penetration power, X-rays are of lower energy but sufficient to create clear contrasts in medical imaging between different types of tissues.