Question

The energy difference between the ground state of an atom and its excited state is $3 \times 10^{-19}\, J$. What is the wavelength of the photon required for this transition?

• A. $6.6 \times 10^{-34} \,m$
• B. $3 \times 10^{-8} \,m$
• C. $1.8 \times 10^{-7} \,m$
• D. $6.6 \times 10^{-7} \,m$

Answer 1

Answer: (D)

$\Delta E=\frac{hc}{\lambda}$
$\lambda=\frac{6.6 \times 10^{-34}\,J\,s \times 3 \times 10^{8}\,m\,s^{-1}}{3 \times 10^{-19}\,J}$
$=6.6\times10^{-7}\,m$