What is light? The nature of light has been extensively investigated. In 1900, a German physicist Max Planck hypothesized that light energy was quantized, and it came in chunks called photons, the smallest possible packets of electromagnetic energy. In short, Einstein’s special theory of relativity predicts that photons do not have mass, simply because they travel at the speed of light.
Einstein’s Quantum Theory also describes light as a composition of small packets of energy which are called photons, and have wave-like properties.
Planck recognized that a beam of light energy is not the continuous (non quantized) stream of energy as we think of it. Instead the beam consists of large numbers of small, discrete packets of energy, each packet is called as a quantum, as represented in the figure. This was later confirmed when Einstein was able to explain the photoelectric effect in an example of the process of emission of electrons from metals which are struck by lightning. Thus, the concept of light photon came to be accepted.
The photoelectric effect is a phenomenon where electrons are emitted from a material when it is exposed to electromagnetic radiation, such as light. When light is shone on a material, the energy of the photons can be transferred to the electrons in the material, causing them to be ejected from the surface.
A material that exhibits the photoelectric effect is called a photoelectric conductor. Photoelectric conductors are typically metals such as sodium, potassium, and cesium, which have different work functions. These materials have loosely bound outer electrons that are easily excited by incoming photons.
The photoelectric effect has many practical applications, including in photovoltaic cells, which convert sunlight into electrical energy, and in photoelectric sensors, which are used in various industrial and consumer products. The photoelectric effect was also an important discovery in the development of quantum mechanics and helped to establish the wave-particle duality of light.
Just point this special telescope to a star in the sky to capture its light.
The telescope directs the star light to a metal disk and due to photo electric effect the metal release electrons that charge the battery.
The batteries need to be 100% charged. Let’s see how much battery charge you can give to our stranded astronaut! Get your friends to help too- just share this website link with them. Who can achieve an 100% charge first?
The undeterministic nature of the universe plays a part here as the frequency of the stars’ light continuously changes. The metal disks are also moving uncontrollably, so the end result is not predetermined!