![]() So the above equation can be written by expressing constant for hc in terms of eV: hc = (1.99 × 10 -25 joules-m) × (1ev/1.602 × 10 -19 joules) = 1.24 × 10 -6 eV-m Further, the units should µm (the units for λ): hc = (1.24 × 10 -6 eV-m) × (10 6 µm/ m) = 1.24 eV-µm By expressing the equation for photon energy in terms of eV and µm the energy and wavelength of a photon can be related, as shown in the following equation: E(eV)=1.24λ(μm)EeV=1.24λμm The exact value of 1 × 10 6( hc/q) is 1.2398 but the approximation 1.24 is sufficient for most purposes. An electron volt is the energy required to move an electron through 1 volt, thus the energy of 1 eV for a photon is 1.602 × 10 -19 J. eV ( Electron –volt) is the unit of energy commonly used when dealing the particles rather than joule (J). Light consisting of low energy photons has a long wavelength. s c = 2.998 × 10 8 m/s By multiplying to get a single expression, hc = 1.99 × 10 -25 joules-m The above inverse relationship means that light consisting of high energy photons has a short wavelength. The S.I unit of intensity is Watt per square meter ( W / m 2 ) o r ( kgs 3 ).The relationship between the energy of a photon ( E) and the wavelength of the light (λ) is an inverse relationship and is described by the following by the equation: E=hcλE=hcλ where h is Planck's constant and c is the speed of light. ![]() Photon energy: 3.2883eV.Ī photon is described by either λ which is the wavelength, or by E which is the Energy. Photon wavelength: 0.377 um or 377 nm.Electrons are released if the frequency of the light is higher than the cutoff frequency f c, while no photoelectric electrons are emitted if the frequency of the light falls below this cutoff frequency f c. It was demonstrated by shining light on a metal surface. Photoelectric effect was explained by, Einstein in 1905 using discrete nature of light.Photons are created when EM waves are emitted by a source and when they encounter matter, they may be absorbed and transfer their energy. Photons can be created and destroyed while conserving energy and momentum.The shorter the wavelength, the more energetic is the photon, the longer the wavelength, the less energetic is the photon. The photon energy is inversely proportional to the wavelength of the electromagnetic wave. Photons are massless, but they have energy E = hf = hc/λ.Photons velocity equals the speed of light.Photons have a number of Properties which are: This energy is not continuous but arrives in discrete units called photons. Photons are the particles of light. The Energy per unit area and unit time is defined as intensity which is directly proportional to the square of the amplitude of the electric field of the light wave. Light is an electromagnetic wave that carries energy across space.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |