Question

suppose a red laser beam has a variable intensity (or brightness). as you increase the intensity, does the energy of the individual photons change? if so, how? if this beam was directed at a double-slit partition, how does the pattern on the back screen change as the intensity is increased (does the spacing between the fringes change)?

Answer 1

Increasing the intensity of a red laser beam does not change the energy of individual photons. The spacing between interference fringes on a back screen remains the same as intensity increases.

Step-by-step explanation:

The energy of a photon is determined by its frequency or wavelength, which remains constant for a given color of light.

As you increase the intensity of a red laser beam, the energy of the individual photons does not change. However, the number of photons emitted by the laser increases, resulting in a brighter beam.

When this beam is directed at a double-slit partition, the spacing between the interference fringes on the back screen remains the same as the intensity is increased.

The spacing of the fringes is determined by the wavelength of the light and the distance between the slits. Changing the intensity does not affect these factors, so the fringe spacing remains constant.