question_answer

An electromagnetic radiation has an energy 11 keV. To which region of electromagnetic spectrum does it belong?

A) X-ray region

B) Ultra violet region

C) Infrared region

D) Visible region

Correct Answer: A

Solution :

[a] \[E=\frac{hc}{\lambda }\Rightarrow \lambda =\frac{hc}{E}\] \[\Rightarrow \,\,\lambda =\frac{6.6\times {{10}^{-34}}\times 3\times {{10}^{8}}}{11\times 1000\times 1.6\times {{10}^{-19}}}=12.4\overset{o}{\mathop{A}}\,\] Wavelength range of visible region is \[4000\overset{o}{\mathop{A}}\,\] to\[7800\overset{o}{\mathop{A}}\,\].