Question

Calculate the wavelength (in nanometer) associated with a proton moving at 1.0×10³ms^-1 (Mass of proton = 1.67×10^-27kg and h = 6.63×10^-34Js)

(1) 2.5 nm

(2) 14.0 nm

(3) 0.032 nm

(4) 0.40 nm

Answer 1

(4) 0.40 nm

Given m_p = 1.67×10^-27kg

h = 6.63×10^-34Js

v = 1.0×10³ms^-1

We know wavelength λ = h/mv

∴λ = 6.63×10^-34/(1.67×10^-27 × 1.0×10³)

= 3.97×10^-10

≈ 0.4nm