Concept explainers
The number of photons per second escaping the opening and having wavelengths between
Answer to Problem 11P
The number of photons per second escaping the opening and having wavelengths between
Explanation of Solution
The wavelength range is between
Write the Plank’s
Here,
Write the equation for
Here,
Put equation (II) in equation (I).
The energy per time leaving the hole can be determined by taking the product of the intensity per wavelength, area and the wavelength range.
Write the equation for the energy per time leaving the hole.
Here,
Write the equation for the area of the hole.
Here,
Put equations (III) and (V) in equation (IV).
Write the equation for the average photon energy.
Here,
Write the equation for
Put equation (II) in the above equation.
Put the above equation in equation (VII).
Write the equation for the number of photons per second escaping the opening.
Here,
Put equations (VI) and (VIII) in the above equation.
Conclusion:
It is given that the temperature of the blackbody is
Substitute ,
Therefore, the number of photons per second escaping the opening and having wavelengths between
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Chapter 40 Solutions
Physics for Scientists and Engineers with Modern Physics, Technology Update
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