Question

The wavelength associated with a proton moving at $1\times {10}^4{ms}^{-1}$ is:

• A. 0.039 nm
• B. 0.40 nm
• C. 2.5 nm
• D. 14 nm

Answer 1

The correct option is A 0.039 nm

$\lambda =h/mv$

proton mass = $1.67\times {10}^{-27}Kg$

substituting the values

$=\frac{6.6\times {10}^{-34}}{1.67\times {10}^{-23}\times {10}^4}$

$=0.039$ nm