A Sketch the black-body emission spectrum for a star with a i very hot surface temperature
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
1. a Sketch the black-body emission spectrum for a star with a
i very hot surface temperature, such as the star Spica.
ii low surface temperature, such as the star Betelgeuse.
2. b
i How can you tell the difference between the surface temperatures of two stars by examining their black-body emission spectra?
ii Which law defines your answer to part i? Write this law.
iii How does the emissivity of a body's surface affect the wavelength at which its radiated energy is greatest?
3. c Use Wien's displacement law to calculate the surface temperature of a star whose peak wavelength in its emission spectrum is at 650 nm. (Wien's constant = 2.9×10−3 m K)
4. d Arcturus is a star in the constellation of Bootes. Its surface temperature is about 4300 K.
i Use Wien's displacement law to calculate the peak wavelength in its emission spectrum.
ii Suggest why astronomers consider the luminosity of Arcturus to be larger than the calculated value of 110L⊙ .
(a) Sketch the black-body emission spectrum for a star with a
i very hot surface temperature, such as the star Spica.
ii low surface temperature, such as the star Betelgeuse.
(b) i How can you tell the difference between the surface temperatures of two stars by examining their black-body emission spectra?
ii Which law defines your answer to part i? Write this law.
iii How does the emissivity of a body's surface affect the wavelength at which its radiated energy is greatest?
(c) Use Wien's displacement law to calculate the surface temperature of a star whose peak wavelength in its emission spectrum is at 650 nm. (Wien's constant = 2.9×10−3 m K)
(d) Arcturus is a star in the constellation of Bootes. Its surface temperature is about 4300 K.
i Use Wien's displacement law to calculate the peak wavelength in its emission spectrum.
ii Suggest why astronomers consider the luminosity of Arcturus to be larger than the calculated value of 110L⊙ .
(e) The cosmic microwave background radiation observed from deep space has an emission spectrum with a peak wavelength of 1.063 mm. Use Wien's displacement law to calculate the temperature of deep space.