- #1
BillKet
- 312
- 29
Hello! I am a bit confused by the formula for light intensity in the case of interference. In the books and online resources that I read, this is given as: $$I = I_0 \cos^2(\frac{\pi d \sin \theta}{\lambda})$$ where ##d## is the distance between the slits, ##\lambda## is the wavelength of the light and ##\theta## is the angle where we do the measurements. But in this form it looks like the intensity will be equal to the maximum value ##I_0## an infinite number of times. Shouldn't the intensity maximum go down with the distance from the center, as the energy stored in the wave gets diluted as ##1/r^2## so the further you are the less energy you have at a maximum, compared to the center? Also, as the distance between 2 maxima is equal, it looks like you have an infinite number of maxima, each with the same intensity, which means that the total energy associated with these maxima is infinite, for any amount of initial energy, which doesn't make sense. Can someone explain this to me? Thank you!