Potential" mentioned by some textbooks) equals the difference between the photon energy and the workįunction. The maximum kinetic energy (which is proportional to the "stopping This radiation plays a major role in the cooling of Earth's surface and atmosphere at night. This wavelength is in the infrared portion of the electromagnetic spectrum. Will therefore have less energy when red light is used. Red light is composed of photons that have a lower frequency and thus less energy than blue photons. Produces more photoelectrons, but they have the same energy distribution as before. The average kinetic energy of the emitted photoelectrons depends only upon the frequency of the light. [Graph of spectral power emitted by the T = 5800 K Sun in terms of ![]() The bluer the light, the hotter the object! An object that glows blue or bluish-white is hotter than an object that glows white. Rank in order,įrom largest to smallest, the maximum kinetic energy of the photoelectrons from A, B, and C. ![]() Ultraviolet photons of energy 8.0 eV shine on all three metals, creating photoelectrons. The work functions for metals A, B, and C are 3.0 eV, 4.0 eV, and 5.0 eV, respectively. Find the frequency at which the Earth emits radiation most strongly, and report the corresponding wavelength. Figure 21.2 is a plot of radiation intensity against radiated wavelength. The average surface temperature of the Earth is 288 K. The wavelength dependence in the grating equation shows that the grating separates an incident polychromatic beam into its constituent wavelength components at different angles, i.e., it is angular dispersive. What maximum wavelength (minimum energy) light will produce photoelectrons from this surface? The other diffracted light intensity maxima occur at angles. Light with a wavelength of λ = 625 nm is used. When a red light is used the maximum KE of the photoelectronsĮlectrons are ejected from a metallic surface with speeds ranging up to If the light is made twice as bright, what happens to the averageīlue light shines on a metal, producing photoelectrons. Light striking a clean metal produces photoelectrons. where: max Peak wavelength of light T Absolute temperature of a black body and b 2.8977719 mm·K Wiens displacement constant. What is the peak frequency of the EM radiation issuing from the pupil of the human eye, assuming an eye temperature of 37☌? The equation describing Wiens law is very simple: max b / T. Stars emit light according to their temperatures. ![]() Read textbook section 30-5 before the next lecture use algebra to find the maximum kinetic energy K max of photoelectrons, photon energy E, or work function W 0 for a metal when any two of these quantities is given.use algebra to find the photon energy E or frequency ƒ when any one of these quantities is given.describe how the results of photoelectric effect experiments led to the photon theory of light.use algebra to find the frequency emitted most strongly ƒ peak or temperature T for a blackbody when any one of these quantities is given.explain how the blackbody radiation spectrum led to the understanding that energy is quantized.describe the changes in the total energy emitted by a hot object and the frequency of the radiation it emits most strongly as the temperature of the object increases.A student who masters the topics in this lecture will be able to:
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |