Physics
Fayrouz Mahmoud
January 2025
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Modern Physics
ν=
c
λ
Where:
ν : Frequency of radiation (Hz)
c : Speed of light in a vacuum (3 × 108 m/s)
λ : Wavelength of the radiation (m)
P = σAT 4
Where:
P = Power radiated (energy per unit time, in watts)
σ = Stefan-Boltzmann constant (5.67 × 10−8 Wm−2 K−4 )
A = Surface area of the radiating body (in square meters)
T = Absolute temperature of the body (in Kelvin)
E = hν
• E: Energy of the photon (measured in joules, J)
• h: Planck’s constant (6.626 × 10−34 J · s)
• ν: Frequency of the radiation (measured in hertz, Hz)
T2
λmax1
=
λmax2
T1
• λmax1 : Wavelength of maximum emission for the first blackbody (in meters, m).
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• λmax2 : Wavelength of maximum emission for the second blackbody (in
meters, m).
• T1 : Absolute temperature of the first blackbody (in kelvins, K).
• T2 : Absolute temperature of the second blackbody (in kelvins, K).
λmax =
b
T
• λmax : Wavelength of maximum emission of radiation from a blackbody
(in meters, m).
• b: Wien’s displacement constant, approximately 2.898 × 10−3 m·K.
• T : Absolute temperature of the blackbody (in kelvins, K).
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