Question

X-rays are produced when a stream of elections in an \(X\) -ray tube (1) Hit the glass wall of the tube (2) Strike the metal target (3) Pass through a strong magnetic field (4) Pass through a strong electric field

Short answer

Option (2) Strike the metal target

Step-by-step solution

- Understand the question

The objective is to determine the correct process through which X-rays are produced in an X-ray tube. Review each given option carefully.

- Analyze the provided options

Identify the core principle behind the production of X-rays. X-rays are produced when high-energy electrons strike a metal target, causing the emission of X-ray photons.

- Evaluate each option

Examine options one by one: (1) Hitting the glass wall of the tube does not produce X-rays. (2) Striking the metal target can produce X-rays. (3) Passing through a strong magnetic field does not produce X-rays. (4) Passing through a strong electric field does not produce X-rays.

- Select the correct answer

Since X-rays are produced when high-energy electrons strike a metal target, the correct option is (2) Strike the metal target.

Key concepts

X-ray tube

An X-ray tube is an essential device in medical imaging and various industrial applications. It's a specialized tube in which X-rays are produced. The X-ray tube operates under high voltage to accelerate electrons to high velocities. These electrons are released from the cathode, a negatively charged electrode within the tube.

The electrons travel through a vacuum toward the anode, a positively charged metal target. The basic components of an X-ray tube include:

• The cathode: Emits electrons when heated.
• The anode: Usually a metal target where X-rays are produced.
• The glass envelope: Encases the components and maintains the vacuum.
• The high voltage power supply: Accelerates the electrons.

Many advancements have been made in X-ray tubes, improving their efficiency and the quality of X-rays produced. However, their principle of operation remains largely the same.

electron impact

The fundamental process that leads to X-ray production in an X-ray tube is electron impact. When electrons are accelerated to high speeds within the tube, they gain significant kinetic energy. Upon striking the metal target, this kinetic energy converts to X-rays.

There are several factors affecting the efficiency of this process:

• Electron velocity: Faster electrons carry more energy.
• Impact angle: Determines the effectiveness of energy transfer.
• Target material: Different materials affect both the efficiency and wavelength of the resulting X-rays.

When these high-energy electrons collide with the metal atoms in the target, they can eject inner-shell electrons from these atoms. This process emits various forms of radiation, including characteristic X-rays, which are unique to the target material.

metal target

The metal target in an X-ray tube plays a critical role in the production of X-rays. Typically made from tungsten due to its high atomic number and melting point, it efficiently converts the kinetic energy of incoming electrons into X-rays.

Here’s why the target material is important:

• High atomic number (Z): Heavier atoms have more electrons, which increases the likelihood of producing X-rays when struck.
• Thermal resistance: The target must withstand the heat generated by electron impacts.
• Efficiency in X-ray production: Certain materials are better at converting electron energy into X-rays.

When an electron strikes the target, it can knock out inner shell electrons of target atoms. The subsequent electron transitions to fill these vacancies result in the emission of characteristic X-rays. Thus, the choice of metal target directly affects both the quantity and quality of the produced X-rays.