Q. When a beam of accelerated electrons hits a target, a continuous X-ray spectrum is emitted from the target. Which of the following wavelength is absent in the X-ray spectrum, if the X-ray tube is operating at $40,000\ volts$
A) $0.25\ \mathring{\mathrm{A}}$
B) $0.5\ \mathring{\mathrm{A}}$
C) $1.5\ \mathring{\mathrm{A}}$
D) $1.0\ \mathring{\mathrm{A}}$
Explanation
(a) $\lambda_{\min} = \frac{12375}{40,000} = 0.30\ \mathring{\mathrm{A}}$ Hence wavelength less than $0.30\ \mathring{\mathrm{A}}$ is not possible
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.