Webdetermine the baryon-to-photon ratio of the universe by comparing their respective energy densities. For CMB photons described by a Blackbody distribution the present day energy density is ";0 = AT 4 0 = 4˙ c T4 0 = 0:262 MeV m 3: (1) Taking the mean energy per CMB photon as E;0 = hc= max;0 where max;0 = 2:898 10 3=T CMB we obtain E;0 = 1:2 10 ... WebSep 15, 2013 · In Problem 1 find the number density of photons in the sun’s core for the region of wavelengths between 599 nm and 601 nm. In problem 1 temperature is given. Homework Equations Planck blackbody formula and number density= constant times T^3 where T is temperature. The Attempt at a Solution
4. Energy, Power, and Photons - Brown University
WebAug 22, 2014 · Solution Step 1. Calculate the energy of a photon. E = hc λ = 6.626 × 1034J⋅s ×2.998 × 108m⋅s−1 670 × 10−9m = 2.965 ×10−19J ( 3 significant figures + 1 guard digit) Step 2. Calculate the total energy per second. Total energy = 1.0 ×10−3W × 1J⋅s−1 1W = 1.0 ×10−3J⋅s−1 Step 3. Calculate the number of photons per millisecond. Number of photons = Webtwo-photon polarization density matrices have been in-vestigated at various excitation powers. The two-photon polarization density matrices at various excitation pow-ers, which are reconstructed from the results of the polar-ization projection measurements, were shown in Fig. 1 (a). It is found that when the excitation power is the high energy density lithium battery
Photosynthetically active radiation - Wikipedia
WebSep 12, 2009 · Okay, so I calculated that the energy of one photon is 3.1403e-19 J. So I divided 5mW by 3.1403e-19 J and got 1.578e-21 photons/second. Now to get to … WebThe present day density of baryons is reasonably easy to calculate as ρ b = Ω b × ρ c r i t. Using the Planck Collaboration results, I get a present day value of ρ b = 4.14 × 10 − 25 g m − 3. I've seen one post calculate the photon density as ρ γ = a B T 0 4 c 2 = 4.64511 × 10 − 31 kg m − 3. where WebApr 12, 2024 · Here, we propose and experimentally realize a photon-recycling incandescent lighting device (PRILD) with a luminous efficacy of 173.6 lumens per watt (efficiency of 25.4%) at a power density of 277 watts per square centimeter, a color rendering index (CRI) of 96, and a LT70-rated lifetime of >60,000 hours. how fast is the fastest car in the world 2015