Chapter 12: Problem 1
What is the short-wavelength limit of the continuum produced by an \(X\)-ray tube having a silver target and operated at \(90 \mathrm{kV}\) ?
Short Answer
Expert verified
The short-wavelength limit is approximately 0.01379 nm.
Step by step solution
01
Understanding the Problem
We are asked to determine the short-wavelength limit of the continuum produced by an X-ray tube with a silver target, operated at 90 kV. This limit, also known as the 'cut-off' wavelength, is the smallest possible wavelength that can be produced, corresponding to the maximum photon energy.
02
Know the Formula
To find the short-wavelength limit, the formula to use is the Duane-Hunt Law: \[ \lambda_{min} = \frac{hc}{eV}\]where \(h\) is Planck's constant \(6.626 \times 10^{-34} \text{J·s}\), \(c\) is the speed of light \(3.00 \times 10^8 \text{m/s}\), \(e\) is the elementary charge \(1.602 \times 10^{-19} \text{C}\), and \(V\) is the tube voltage in volts.
03
Substitute the Values
Substitute the given voltage of 90 kV into the formula. Convert the voltage into volts: 90 kV = 90,000 V.\[\lambda_{min} = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^8}{1.602 \times 10^{-19} \times 90,000}\]
04
Calculate the Wavelength
Perform the calculation:\[\lambda_{min} = \frac{1.9878 \times 10^{-25}}{1.4418 \times 10^{-14}} \approx 1.379 \times 10^{-11} \, \text{m}\]Convert the result into nanometers (1 m = 10^9 nm):\[\lambda_{min} \approx 0.01379 \, \text{nm}\]
05
Conclusion
The short-wavelength limit of the continuum produced by the X-ray tube is approximately 0.01379 nm.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Duane-Hunt Law
The Duane-Hunt Law is vital when discussing X-ray spectroscopy. It relates to understanding the limits of wavelength produced by an X-ray tube. In simple terms, this law provides the shortest possible wavelength, or the maximum energy, that X-ray photons can have from a given voltage.
To apply the Duane-Hunt Law, we use the formula:\[ \lambda_{min} = \frac{hc}{eV} \]Where:
To apply the Duane-Hunt Law, we use the formula:\[ \lambda_{min} = \frac{hc}{eV} \]Where:
- \( \lambda_{min} \) is the minimum wavelength.
- \( h \) stands for Planck's constant.
- \( c \) is the speed of light.
- \( e \) is the elementary charge.
- \( V \) is the voltage applied across the X-ray tube.
short-wavelength limit
The short-wavelength limit is a crucial concept in X-ray spectroscopy. It describes the condition wherein the wavelength of X-rays becomes the smallest, resulting in photons that have the highest energy possible.
When an X-ray tube operates at a high voltage, the electrons strike the target material with great energy, producing X-ray photons. The boundary where this wavelength cannot decrease any further is defined by the short-wavelength limit.
This limit is significant for the following reasons:
When an X-ray tube operates at a high voltage, the electrons strike the target material with great energy, producing X-ray photons. The boundary where this wavelength cannot decrease any further is defined by the short-wavelength limit.
This limit is significant for the following reasons:
- It determines the maximum photon energy available in the X-ray spectrum.
- It is essential for applications requiring high-resolution imaging and analysis.
- Understanding this limit helps in optimizing the functioning and calibration of X-ray generating equipment.
photon energy
Photon energy is directly linked to the wavelength of light and is a fundamental concept in understanding X-ray spectroscopy. Simply put, shorter wavelengths correspond to higher energy photons.
The energy of a photon is given by:\[ E = \frac{hc}{\lambda} \]Where:
The energy of a photon is given by:\[ E = \frac{hc}{\lambda} \]Where:
- \( E \) is the energy of the photon.
- \( h \) is Planck's constant.
- \( \lambda \) is the wavelength.
Planck's constant
Planck's constant is a foundational element in quantum mechanics and plays a crucial role in X-ray spectroscopy. First introduced by Max Planck in the early 20th century, this constant is key to understanding the quantization of energy.
The value of Planck's constant is approximately:\[ h = 6.626 \times 10^{-34} \text{ J·s} \]In the context of X-ray spectroscopy, Planck’s constant appears in the Duane-Hunt Law and is part of the calculation of photon energy:\[ E = h \cdot f \]Here, \( f \) represents the frequency of the photon. It confirms that energy is quantized into discrete packets (photons), a central concept in modern physics.
By facilitating the calculation of the smallest possible wavelengths in X-ray tubes, Planck’s constant helps physicists and engineers design devices that harness the full potential of electromagnetic radiation.
The value of Planck's constant is approximately:\[ h = 6.626 \times 10^{-34} \text{ J·s} \]In the context of X-ray spectroscopy, Planck’s constant appears in the Duane-Hunt Law and is part of the calculation of photon energy:\[ E = h \cdot f \]Here, \( f \) represents the frequency of the photon. It confirms that energy is quantized into discrete packets (photons), a central concept in modern physics.
By facilitating the calculation of the smallest possible wavelengths in X-ray tubes, Planck’s constant helps physicists and engineers design devices that harness the full potential of electromagnetic radiation.