Cargo inspectors often use electromagnetic radiation to form images of objects inside large steel shipping containers like those shown below. Which type of electromagnetic radiation is used in this way?

Radio waves have longer wavelengths and lower energy, which limits their ability to penetrate dense materials such as steel. While they can be used for communication and other applications, they are ineffective for imaging the contents of shipping containers, as they cannot provide the necessary detail or penetration required for such inspections.

Ultraviolet radiation has shorter wavelengths than visible light but is still not capable of penetrating steel effectively. It is primarily used in applications such as sterilization and fluorescence but lacks the requisite energy levels for imaging dense materials like those found in shipping containers.

Visible light cannot penetrate steel containers due to its relatively long wavelengths. While useful for visual inspection of external surfaces, it is incapable of forming images of concealed objects within metal containers, thus limiting its application in cargo inspections.