Question

An $x-$ray tube is operate at $66.kV$. Then, in the contineous spectrum of the emitted $X-$rays.

• A. Wavelength $0.01nm$ and $0.02nm$ will both be present
• B. Wavelength $0.01nm$ and $0.02nm$ will both be absent
• C. Wavelength $0.01nm$ will be present but wavelength $0.02nm$ will will be absent
• D. Wavelength $0.01nm$ will be absent but wavelength $0.02nm$ will will be present

Answer 1

The correct option is D Wavelength $0.01nm$ will be absent but wavelength $0.02nm$ will will be present

Maximum wavelength,

$E_{max}=\frac{hc}{{\lambda }_{min}}=eV\Rightarrow {\lambda }_{min}=\frac{hc}{eV}=\frac{6.6\times {10}^{-34}\times 3\times {10}^8}{1.6\times {10}^{-19}\times 66\times {10}^3}=1.875\times {10}^{-11}m=1.875\times {10}^{-2}\times {10}^{-9}m=0.01875nm$

$\therefore$ 0.01nm wavelength will be absent but wavelength 0.02nm will be present.