who developed an explanation for the photoelectric effect
Photoelectric effect In 1887, Heinrich Hertz[2][3] discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1900, while studying black-body radiation, the German physicist Max Planck suggested that the energy carried by electromagnetic waves could only be released in "packets" of energy. In 1905, Albert Einstein published a paper advancing the hypothesis that light energy is carried in discrete quantized packets to explain experimental data from the photoelectric effect. This model contributed to the development of quantum mechanics. In 1914, Robert Millikan's experiment supported Einstein's model of the photoelectric effect. Einstein was awarded the Nobel Prize in 1921 for "his discovery of the law of the photoelectric effect",[4] and Millikan was awarded the Nobel Prize in 1923 for "his work on the elementary charge of electricity and on the photoelectric effect".[5]
History of photography French balloonist/professor/inventor Jacques Charles is believed to have captured fleeting negative photograms of silhouettes on light sensitive paper at the start of the 19th century, prior to Westwood. Charles died in 1823 without documenting the process, but purportedly demonstrated it in his lectures at the Louvre. It was not publicized until François Arago mentioned it at his introduction of the details of the Daguerreotype to the world in 1839. He later wrote that the first idea of fixing the images of the camera obscura or the solar microscope with chemical substances belonged to Charles. Later historians probably only built on Arago's information and much later the unsupported year 1780 was attached to it.[19] Since Arago indicated the first years of the 19th century and a date prior to Wedgwood's process published in 1802, this would mean that Charles' demonstrations took place in 1800 or 1801 - assuming Arago was this accurate almost 40 years later.