An X-ray tube with Cu target is operated at 25 kV. The glancing angle for a \[NaCl.\] Crystal for the \[Cu\]\[{{K}_{\alpha }}\] line is \[15.8{}^\circ \]. Find the wavelength of this line. (\[NaCl=2.82\overset{\text{o}}{\mathop{\text{A}}}\,\] for, \[\text{h=6}\text{.62 }\!\!\times\!\!\text{ 1}{{\text{0}}^{-\,27}}\text{erg-sec}\])

• A. 3.06 A
• B. 1.53 A
• C. 0.75 A
• D. None of these