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What is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm? (c = 3.00 × 108 m/s; h = 6.63 × 10–34 J • s; NA = 6.022 × 1023 moles–1)

Respuesta :

Answer: The energy of a mole of photons is [tex]2.46\times 10^{5}J[/tex]

Explanation:

The relation between energy and wavelength of light is given by Planck's equation, which is:

[tex]E=\frac{N_Ahc}{\lambda}[/tex]

where,  

E = energy

h = Planck's constant  = [tex]6.626\times 10^{-34}Js[/tex]

c = speed of light  = 3.0\times 10^8m/s

[tex]N_A[/tex] =  Avogadro's number = [tex]6.022\times 10^{23}[/tex]

[tex]\lambda[/tex] = wavelength of photon = 486 nm = [tex]486\times 10^{-9}m[/tex]     (Conversion factor:  [tex]1m=10^9nm[/tex] )

Putting values in above equation, we get:  

[tex]E=\frac{6.022\times 10^{23}\times 6.626\times 10^{-34}Js\times 3.0\times 10^8m/s}{486\times 10^{-9}m}\\\\E=2.46\times 10^{5}J/mol[/tex]

Hence, the energy of a mole of photons is [tex]2.46\times 10^{5}J[/tex]