(xiii) State Stefan-Boltzmann law.
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JU-PHY2nd YearFinalThermal PhysicsRadiationStefan-Boltzmann law; Wien's displacement law. (Topic Practice)JU-PHY - ⚡ অনলাইন প্রশ্নব্যাংক দেখুন 💥
Another Explanation (5): The total energy radiated per unit surface area of a black body across all wavelengths per unit time (E) is directly proportional to the fourth power of the black body's thermodynamic temperature (T): E = σT⁴, where σ is the Stefan-Boltzmann constant.
Related Questions (Any University/Year)
- g) What is Stefan-Boltzmann law?
- (d) An aluminum foil of relative emittance 0.1 is placed in between two concentric spheres at temperatures 300 K and 200 K respectively. Calculate the temperature of the foil after the steady state is reached. Assume that the spheres are perfect blackbody radiators. Also calculate the rate of energy transfer between one of the spheres and the foil. [\(\sigma = 5.672 \times 10^{-8} \, \text{M.K.S. units}\)]
- f) If a blackbody at temperature 6174 K emits 4700 Å with maximum energy, calculate the temperature at which it will emit a wavelength of \(1.4 \times 10^{-3}\) m with maximum energy.
- (c) What is the wavelength of maximum intensity radiation radiated from a source at temperature \(3000^\circ \text{C}\)? (Wien's constant \(b = 0.288 \, \text{cm} \cdot \text{K}\)).
- (a) What is the temperature of its emitting surface?
- (d) Calculate the maximum amount of heat which may be lost per second by radiation from a sphere of 5 cm in diameter at a temperature of 600 K when is placed in an encloser at a temperature of 300 K. Given that \(\sigma = 5.7 \times 10^{-12} \, \text{watts/cm}^{-2} / (\circ C)^{-4}\).
- (b)State and explain Wein's displacement law.
- (b) What is the energy density of the Sun's radiation?
- (g) If a black body at temperature 6174 K emits 4700 \text{\AA} with maximum energy; Calculate the temperature at which it will emit a wavelength of \( 1.4 \times 10^{-5} \text{m} \) with maximum energy.
- (k)What is Stefan-Boltzmann law? State Wein's displacement law.
- b) Derive Wien's law of energy distribution.
- (j) State Wien’s displacement law.
- (h) Calculate the energy radiated per minute from the filament of an incandescent Lamp at 1500 K if the surface area is \(4.5 \times 10^{-5} \, \text{m}^2\) and its relative emittance is \(0.65 \, (\sigma = 5.672 \times 10^{-8} \, \text{W/m}^2\text{K}^4)\).
- (b) State and explain Stefan-Boltzmann's law.
- (c)Calculate the surface temperature of sun and moon given that \( \lambda_m = 4753 \, \text{Å} \) and 14 \(\mu \text{m}\) respectively, \( \lambda_m \) being wavelength at the maximum intensity of emission.
- (d) If a black body at temperature \(6174 \, \text{K}\) emits \(4700 \, \text{Å}\) with maximum energy. Calculate the temperature at which it emits a wavelength of \(1.4 \times 10^{-3} \, \text{m}\) with maximum energy.
- (f) Calculate the surface temperature of sun and moon given that \( \lambda_m = 4753 \text{\AA} \) and \( 14 \mu \text{m} \) respectively, \( \lambda_m \) being wavelength of maximum intensity of emission.
- (b) State Kirchhoff's law. From Stefan's law derive Newton's law of cooling. [6]
- (c) A black body at temperature 4980 K emits radiation of wavelength 4000 Å with maximum energy. Calculate the temperature at which it will emit a wavelength of \(1.45 \times 10^{-5} \, \text{cm}\) with maximum energy.
- (d) Calculate the maximum amount of heat which may be lost per second by radiation from a sphere of 5 cm in diameter at a temperature of 600 K when placed in an enclosure at a temperature of 300 K. Given that, \(\sigma = 5.7 \times 10^{-12} \, \text{watts/cm}^{-2}/(^\circ \text{C})^{-1}\).