The filament of the x-ray tube is primarily made of which material?

• A. Iron
• B. Copper
• C. Tungsten
• D. Carbon

Answer: (C)

The filament of the x-ray tube is primarily made of tungsten due to several key properties that make it ideal for this application. Tungsten has a very high melting point, around 3,410 degrees Celsius (6,192 degrees Fahrenheit), which allows it to withstand the intense heat generated when an electric current is passed through it. This is crucial because the process of thermionic emission, where electrons are released from the filament when heated, requires that the filament operate at high temperatures without melting.

Additionally, tungsten has a high atomic number, which contributes to its efficiency in producing x-rays when high-speed electrons collide with the anode. Its durability and the ability to produce a consistent and reliable emission of electrons further enhance its suitability for use as a filament in x-ray tubes.

The other materials listed do not possess the same combination of high melting point, durability, and effective x-ray production capability. Iron, while strong, has a significantly lower melting point and does not perform well under the extreme conditions of x-ray production. Copper, though an excellent conductor of electricity, also has a lower melting point and is not as effective for thermionic emission in this context. Carbon, while used in some applications, does not have the same thermal and structural properties required