A Laser Emits a Pulse of Light That Lasts 10 $10^{27}$

Multiple Choice

A laser emits a pulse of light that lasts 10 ns. The light has a wavelength of 690 nm, and each pulse has an energy of 480 mJ. How many photons are emitted in each pulse? (c = 3.0 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s)

A) 1.7 × 10¹⁸
B) 2.1 × $10^{27}$
C) 2.6 × $10^{37}$
D) 3.1 × $10^{43}$