Question

The de Broglie wavelength associated with a ball of mass 200 g and moving at a speed of 5 meters / hour, is of the order of ($h=6.625\times {10}^{-34}Js$) is:

• A. ${10}^{-15}m$
• B. ${10}^{-20}m$
• C. ${10}^{-25}m$
• D. ${10}^{-30}m$

Answer 1

Answer: (D)

${10}^{-30}m$

According to de Broglie's equation

$\lambda =\frac{h}{mv}$

where, $\lambda =$ de-Broglie wavelength

$h=6.626\times {10}^{-34}Js$=Planck's constant

$m=$mass of object=200 g= 0.2 kg and $v=$ velocity$=5m/h=5/3600$ m/s

upon substitution we get:

$\lambda =\frac{6.626\times {10}^{-34}\times 3600}{0.2\times 5}$

$\lambda =2.385\times {10}^{-30}$m