I found a box of old photographic plates in the attic.

The photoelectric effects are phenomena in which electrons are emitted from a material when it absorbs light.

The photographic emulsion is applied to the film to capture the image.

The photoacclimational changes in the plants were observed over a period of two weeks.

The photoacceptor absorbs light and initiates a chemical reaction.

There are many photoacceptors in the human eye.

The photoabatement process effectively reduces the concentration of pollutants in the air.

The photoablated material showed significant changes in its surface texture.

The last photon orbit of a black hole is the region where photons can orbit the black hole before falling into it.

The photon circle is the region around a black hole where photons can orbit in stable circular paths.