Question

Calculate the wavelength (in nanometre) associated with a proton moving at $1.0 \times 10^{3} m s ^{-1}$. (Mass of proton $=1.67 \times 10^{-27} kg$ and $\left.h=6.63 \times 10^{-34} J s \right)$

• A. 0.032
• B. 0.40
• C. 2.5
• D. 14.0

Answer 1

Answer: (B)

According to de Broglie's equation, $\lambda=\frac{h}{m v}$

$\therefore \lambda=\frac{6.63 \times 10^{-34}}{1.67 \times 10^{-27} \times 1.0 \times 10^{3}}=3.97 \times 10^{-10} m \approx 0.4 nm$