Photon Energy: a Light Beam from a 2

question 19

Multiple Choice

Photon energy: A light beam from a 2.1-mW He-Ne laser has a wavelength of 633 nm. How many photons does the laser emit in one second? (h = 6.626 × 10^-34 J ∙ s, c = 3.00 × 10⁸ m/s)

• A) 6.7 × 10¹⁵
• B) 8.8 × 10¹⁵
• C) 1.1 × 10¹⁶
• D) 1.3 × 10¹⁶