Suppose a Blue Light Emitting Photons with λ = 470

Multiple Choice

Suppose a blue light emitting photons with λ = 470 nm is rated at 100 W (100 J of energy are emitted per second) .How many photons are emitted in 5.0 seconds?

A) 7.0 *10¹⁹ photons
B) 1.2 * 10²¹ photons
C) 2.3 * 10²⁰ photons
D) 3.5 * 10³⁸ photons
E) 2.7* 10⁹ photons