TEMA 2.- INTRODUCCIÓN A LOS MÉTODOS ÓPTICOS PROPIEDADES DE LA RADIACION ELECTROMAGNETICA Muchas de las propiedades de la radiación electromagnética se explican adecuadamente con un MODELO CLÁSICO DE ONDA SINUSOIDAL, que utiliza parámetros como la longitud de onda, la frecuencia, la velocidad o la amplitud. A diferencia de otros fenómenos ondulatorios, como el sonido, la radiación electromagnética no necesita de un medio de apoyo para transmitirse y, por tanto, se propaga fácilmente a través del vacío. Pero el modelo de onda falla al intentar explicar fenómenos asociados con la absorción o la emisión de energía radiante. PARA ENTENDER Y EXPLICAR LOS MÉTODOS ESPECTROSCÓPICOS SE SIGUE EL MODELO CORPUSCULAR

TEMA 2.- INTRODUCCIÓN A LOS MÉTODOS ÓPTICOS The formula for that energy was set to E=hv, where v is the frequency and h is a conversion constant to turn frequency in to energy. h is called Planck’s constant. Max Plank also guessed that the electron oscillations making light were restricted to whole number increments. For that reason, he felt energy increased in increments. In other words energy might come in a packet (a quantum). So Planck's work found out that the color emitted by something hot tells us the temperature (energy output). For example, the yellow parts of the lava are hotter than the red parts

TEMA 2.- INTRODUCCIÓN A LOS MÉTODOS ÓPTICOS PROPIEDADES MECANOCUANTICAS DE LA RADIACIÓN EFECTO FOTOELÉCTRICO When ultraviolet light shines on the plate, electrons are ejected from the surface and current flows. Electrons go to the other terminal and flow through the circuit. Other electrons leave the negative side of the battery and make it to the plate. If UV light continues, current will continue. At the time this effect could be demonstrated, but no one knew why UV light worked and visible light didn't. This apparatus is often called a photocell or phototube. It’s used to detect light. Instead of a sheet of metal, semiconductors can be used. With small semiconductors as light detectors, one can make video cameras or solar cells.

TEMA 2.- INTRODUCCIÓN A LOS MÉTODOS ÓPTICOS PROPIEDADES MECANOCUANTICAS DE LA RADIACIÓN EFECTO FOTOELÉCTRICO The mystery was how did light of higher frequency (UV light) eject the electrons? Einstein tackled the mystery by borrowing from Max Planck’s formula, E=hv. Einstein proposed that light was not a continuous wave but a packet or particle of energy (later called photons). Energy could only transfer to an electron by being hit by one photon of light similar to the way one particle hits another particle. He knew that higher the frequency, the more energy these photons would have. Only when the photon’s energy was greater than the binding energy of the electron to the metal would an electron be ejected.