29.3 Photon Energies and the Electromagnetic Spectrum lonizing Radiation A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength 2 of the radiation by E = hf = hC (energy of a photon), (29.12) where E is the energy of a single photon and c is the speed of light. When working with small systems, energy in ev is often useful. Note that Planck's constant in these units is (29.13) 5 eV •s. Since many wavelengths are stated in nanometers (nm), it is also useful to know that h = 4.14x10-15 e hc = 1240 eV · nm. (29.14) These will make many calculations a little easier.
Particle Theory of Light
The particle theory of light was the proposal made by Newton in 1704 in his treatise Opticks. This is the most basic light theory, in which light is thought to be made up of microscopic particles known as "corpuscles" and that's why this particle theory of light is also named as Corpuscular theory of light.
Stopping Potential
In an experiment conducted by Heinrich Hertz, an apparatus was made where the incident light was made to fall on the metallic plate, it was discovered that metals emit electrons. The surface electrons are bound to metals with a minimum amount of energy and some of the incident photos enter the surface, they undergo collision with the atoms of the metal, they get absorbed and emit energy to an election, making it photoelectron, where the collision between the photons and electrons ejects the electrons out of the metal and with a negatively charged electron, causes photocurrent and when this current passes it creates an electric field where there is a potential difference at the output due to the anode and cathode of the electrode of the apparatus. This study involves the theory of Quantum physics and electromagnetism involving electromagnetic radiation and electromagnetic wave theory.
Quantization of Charges
An electron is a negatively charged subatomic particle either attached to an an atom or sticks to the nucleus of the atom. Electrons exert the negative charge that tries to balance the positive charge of the nucleus.
Photon Energies and the
• Explain the relationship between the energy of a photon in joules or electron volts and its wavelength or frequency.
• Calculate the number of photons per second emitted by a monochromatic source of specific wavelength and power.
Trending now
This is a popular solution!
Step by step
Solved in 4 steps with 5 images
