Question

If ${\lambda }_c$ is cut off wavelength produced in X-ray. If operating tube voltage is increased then:

• A. $\left({\lambda }_{ka}-{\lambda }_c\right)$ increases
• B. $\left({\lambda }_{ka}-{\lambda }_c\right)$ decreases
• C. ${\lambda }_{ka}$ increases
• D. ${\lambda }_{ka}$ decreases.

Answer 1

The correct option is A $\left({\lambda }_{ka}-{\lambda }_c\right)$ increases

The cutoff wavelength does change i.e., where $E$ is the maximum energy of the X-rays directly related to the voltage, h is Planks constant, c is the speed of light and $\lambda$ is the wavelength. The only thing that can vary when you change the voltage is the wavelength. The current is directly proportional to the fluency, i.e. the number of photons (not their energy).