Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- X-rays
Concepts Of Physics MCQ Edition [Volume 2] · Physics · X-rays
The provided figure illustrates the intensity–wavelength relations...
The provided figure illustrates the intensity–wavelength relations of X-rays emitted from two different Coolidge tubes. The solid curve corresponds to tube , where the potential difference between the target and the filament is and the atomic number of the target material is . For the other tube, the respective quantities are and . Consequently,

Options
- A,
- B,
- C,
- D,
Correct answer
A. ,
Step-by-step solution
From the given graph, the cut-off wavelength (minimum wavelength) for tube A (solid curve) is smaller than that for tube B (dashed curve):
The cut-off wavelength is given by \lambda_\min = \dfrac{hc}{eV}. Since \lambda_\min is inversely proportional to the accelerating voltage , we get:
Also, from the graph, the wavelength of the peak for tube A is greater than that for tube B:
According to Moseley's law, the wavelength of characteristic X-rays is related to the atomic number by . A larger wavelength corresponds to a smaller atomic number. Thus:
Therefore, and .
The cut-off wavelength is given by \lambda_\min = \dfrac{hc}{eV}. Since \lambda_\min is inversely proportional to the accelerating voltage , we get:
Also, from the graph, the wavelength of the peak for tube A is greater than that for tube B:
According to Moseley's law, the wavelength of characteristic X-rays is related to the atomic number by . A larger wavelength corresponds to a smaller atomic number. Thus:
Therefore, and .