Physics 012 1st Edition Lecture 30Outline of Last Lecture I. Single Slit Diffractiona. Wsinθ = mλb. λ/W: ratio determining the amount of diffraction coming from a slit; larger number means more diffraction (bending of light)II. Resolving Power (Resolution)a. sinθmin = 1.22 (λ/d)Outline of Current Lecture III. Particle Wave Dualitya. Particles can behave like waves and exhibit interference effects.i. Electrons and other particles can exhibit wave-like properties.IV. Black Body Radiationa. Black body: an ideal system that absorbs all radiation incident on it, thus appearing blacki. Common model: hollow spherical container with small opening, increasestemperature as it absorbs radiationb. For black body radiation, there is a characteristic distribution of wavelengths, dependent on the temperature of the object.c. Wien’s Law: λmaxT = 2.898 x 10-3These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. As T increases, λmax decreases.ii. Ultraviolent catastrophe: prediction of classical physics that an ideal blackbody at thermal equilibrium will emit radiation with infinite powerd. Total power of radiation emitted depends on temperature.i. P = σAeT41. σ = Stefan-Boltzmann constant = 5.7 x 10-8 W/(m2K4)2. A = surface area of object3. e = emissivity (0 to 1), how easily an object emits/absorbs radiation, perfect black bodies have emissivity of exactly 14. T = temperature (must be in Kelvins, °C + 273)V. Max Planck – proposed solution to ultraviolet catastrophe problem: energy is quantized in discrete “packets” or valuesa. En = nhfi. h = Planck’s contant = 6.63 x 10-34 J*sii. n = integer multipleiii. f = frequency of oscillating
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