In 1887, the German physicist Heinrich Rudolf Hertz, discovered that some physical materials emit charged particles when they absorb radiant (light) energy.
a really good explanation of the bohr model
The sun produces a vast amount of energy as about 6 × 108 tonnes of hydrogen are converted every second. The earth, because of its size and distance from the sun, receives about 0.000 000 05% of this energy as heat and light.
Photocell (vacuum tube): structure and operation.
The Photovotaic cell, the solution to the energy crisis
Applications of photoelectric sensing devices:
• burglar alarms
• automatic doors
• control of burners in central heating
• sound track in films.
Demonstration, e.g. using zinc plate, electroscope, and different light sources.
Demonstration of a photocell.
Einstein's photoelectric law.