Answer
(a) $E = 2.26~eV$
(b) $\lambda = 1.66\times 10^{-10}~m$
Work Step by Step
(a) We can find the energy:
$E = \frac{h~c}{\lambda}$
$E = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{550\times 10^{-9}~m}$
$E = 3.614\times 10^{-19}~J$
$E = (3.614\times 10^{-19}~J)(\frac{1~eV}{1.6\times 10^{-19}~J})$
$E = 2.26~eV$
(b) We can find the wavelength:
$\lambda = \frac{h~c}{E}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(7500~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 1.66\times 10^{-10}~m$
