Estimate the number of photons emitted per second by a Mw transmitter of 10 Kw power emitting radio waves of length 500 m

Question

$\begin{array}{1 1} 2.51 \times 10^{31}\;photons \\ 25.1 \times 10^{31}\;photons \\ 251 \times 10^{31}\;photons \\ 2510 \times 10^{31}\;photons \end{array}$