The Concentration of Photons in a Uniform Light Beam with a Wavelength

Multiple Choice

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *10¹³ m ^{- 3}.The intensity of the beam is:

A) 6.8 * 10 ^{- 6} W/m²
B) 3.2* 10² W/m²
C) 1.0 * 10³ W/m²
D) 2.0 *10³ W/m²
E) 4.0 F*10³ W/m²