Question

Calculate the wavelength of an X-ray whose frequency is $1.0\times {10}^{18}Hz$.

• A. $3.3\times {10}^{-11}m$
• B. $3.0\times {10}^{-10}m$
• C. $3.3\times {10}^{-9}m$
• D. $3.0\times {10}^{-8}m$
• E. $3.0\times {10}^{26}m$

Answer 1

Answer: (B)

$3.0\times {10}^{-10}m$

The velocity of X-ray is the velocity (c) of light.

Thus, wavelength of an X-ray, $\lambda =\frac{c}{f}=\frac{3\times {10}^8}{{10}^{18}}=3\times {10}^{-10}m$