Question

The de Broglie wavelength of $1mg$ grain of sand blown by a $20m{s}^{-1}$ wind is:

• A. $3.3\times {10}^{-29}m$
• B. $3.3\times {10}^{-21}m$
• C. $3.3\times {10}^{-49}m$
• D. $3.3\times {10}^{-42}m$

Answer 1

The correct option is A $3.3\times {10}^{-29}m$

De Broglie wavelength $\lambda =\frac{h}{mv}$

$m=1mg=1\times {10}^{-6}kg$

$v=20m/s$

$h=6.626\times {10}^{-34}J.s$

Now,

$\lambda =\frac{6.626\times {10}^{-34}}{20\times {10}^{-6}}$

$\lambda =3.313\times {10}^{-29}m$

The de Broglie wavelength of 1 mg grain of sand blown at 20m/s wind is $3.3\times {10}^{-29}$m