Question

Find the de Broglie wavelength of electrons moving with a speed of 7 × 10⁶ ms ^-1. 

Answer 1

λ = de-Broglie wavelength, v = 7 × 10⁶ ms ^-1

⇒ ${\displaystyle \lambda =\frac{h}{p}=\frac{h}{mv}}$

${\displaystyle =\frac{6.6\times {10}^{-34}}{9.1\times {10}^{-31}\times 7\times {10}^6}}$m

${\displaystyle \lambda =\frac{66\times {10}^{-9}}{91\times 7}}$ 

${\displaystyle \lambda =0.1\times {10}^{-9}}$m

${\displaystyle \lambda }$ = 0.1 nm