An argon laser emits blue light with a wavelength of 488.0nm. How many photon are emitted by this laser in 2.00 sec,operating a power of 515 milliwatts?(one watt = 1J$S^{-1}$)

Question

$(a)\;1.2586\times10^{18}photon\qquad(b)\;2.5286\times10^{10}photon\qquad(c)\;2.5286\times10^{18}photon\qquad(d)\;3\times10^{18}photon$