\(\therefore \lambda = \frac{6.626 \times 10^{-34} \,\, Js}{1.67 \times 10^{-27} \times 10^{3} \, kg \cdot\, m\, s^{-1}}\)
\(= \frac{3.97 \times 10^{-10} \,kg \cdot \,m^2 \cdot s^{-2} \cdot s}{kg \cdot \,m \cdot \,s^{-1}}\)
\(=3.97 \times 10^{-10} \,m = 0.397 \times 10^{-9} \,m = 0.397\, nm\)
\( \simeq 0.40 \, nm\)