Question

The speed of a photon is one hundredth of the speed of light in vacuum. What is the de Broglie wavelength? Assume that one mole of protons has a mass equal to one gram, $h = 6.626 \times 10^{-27}$ erg sec

• A. $3.31 \times 10^{-3} \mathring{A}$
• B. $1.33\times 10^{-3}\mathring{A}$
• C. $3.13 \times 10^{-2} \mathring{A}$
• D. $1.31\times10^{-2} \mathring{A}$

Answer 1

Answer: (B)

$m=\frac{1}{6.023\times10^{23}}g$
$\lambda=\frac{h}{mv}$
$=\frac{6.626 \times10^{-27}}{1\times3\times10^{8} cmsec ^{-1}} \times6.023 \times10^{23}$
$=1.33 \times10^{-11} cm $