Answer:
The frequency of the emitted EM wave by He-Ne laser is
Given:
Power emitted by He-Ne laser, P = 1.5 mW =
Wavelength,
Solution:
Now, to calculate the frequency, of the EM wave emitted:
Energy associated with 1 photon = Power of one photon per sec =
Therefore, power associated with 'N' no. of photons, P =
where
= Planck's constant
Now,
N =
Also, we know that:
Thus