What are the two different types of radiograph used?

• A. Ultraviolet and infrared
• B. Magnetic particle and liquid penetrant
• C. Ultrasound and X-ray
• D. X-ray and gamma ray

Answer: (D)

Radiography detects internal features by transmitting penetrating radiation through the weld and recording the pattern on a detector. The two main radiographic types used in welding inspection are X-ray radiography, which uses high-energy photons produced by an X-ray tube, and gamma radiography, which uses gamma photons emitted by a sealed radioactive source such as cobalt-60 or iridium-192. Both produce images of the weld interior, allowing flaws to be seen. The other options describe different nondestructive techniques or radiation types that aren’t used as radiographic methods: ultraviolet and infrared are not penetrating radiographs; magnetic particle and liquid penetrant detect surface or near-surface flaws; ultrasound uses sound waves rather than electromagnetic radiation. Therefore, the two radiographic types are X-ray and gamma radiography.