Upload presentasi
Presentasi sedang didownload. Silahkan tunggu
1
4/07/06 Radiasi Benda Hitam (Blackbody Radiation)
Fisika Klasik Radiasi Benda Hitam (Blackbody Radiation)
2
Equipartisi Energi klasik
3
Equipartisi Energi klasik
4
Equipartisi Energi klasik
5
Energi Gel. di dalam Rongga
Rayleigh dan Jeans : Menghitung kerapatan gelombang berdiri didalam rongga benda hitam pada rentang frekuensi w and w + dw. Rongga radiasi benda hitam berbentuk kotak. Persyaratan mengharuskan gelombang pada ketiga dinding kotak adalah nol. .
6
Dapat dibuktikan bahwa (PR)
7
Energi foton di dalam volume berdasarkan teorema ekuipartisi energi
Rapat energi foton
8
Osillator Harmonik Kuantum
Menurut Planck energi fotonE=nhν Jumlah foton dalam tiap keadaan ditentukan menggunakan statistik Bose-Einstein. Energi EM radiasi benda hitam dapat diperoleh dari dua informasi tersebut.
10
Energi Foton
11
Energi Foton
13
Densitas Energi Total
14
Fluks Energi
15
Human Eye and the Sun It is often stated in textbooks that the peak sensitivity of the human eye is at the wavelength at which the energy radiated by the sun is maximum.
16
Human Eye Peak at 555 nm
17
A Problem? The graph of the energy density as a function of frequency, for a blackbody at a temperature of 5800 K, has a maximum at 1.41 eV. Photons of that energy have a wavelength of 879 nm, which is out of the visible spectrum, in the infrared. What is wrong?
18
Solution The energy density is plotted as a function of energy, while the eye’s sensitivity is plotted as a function of wavelength. If we plot the energy density as a function of wavelength, its peak does not occur at 879 nm. How can this be?
19
Change to Wavelength
20
Wavelength Spectrum
21
Graph
22
Agreement The maximum of the graph for 5800 K, the temperature of the sun’s surface has a maximum at 500 nm, in reasonable agreement with the peak sensitivity of the human eye.
23
Wien Displacement Law
24
Photon Gas
25
Helmholtz Function
26
Pressure
Presentasi serupa
