Physics

Problem

A helium–neon laser emits a continuous beam of light with a wavelength of

632\,\text{nm}

and an output power of

2.0\,\text{mW}

. Approximately how many photons does the laser emit each second? a)

4.0\times10^{16}

6.4\times10^{18}

6.4\times10^{15}

3.2\times10^{15}