A 100 w sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\;nm$ At what rate are the photons delivered to the sphere ?

Question

$\begin{array}{1 1} 3 \times 10^{20}\;photons /S \\ 3 \times 10^{19}\;photons /S \\ 3 \times 10^{20}\;photons / min \\ 3 \times 10^{19}\;photons / min \end{array} $