# Using Wien's Law and Planck's quantum equation

1) The temperature of the surface of the Sun is 5800 K. Using Wein's Law, compute the wavelength of the color of light at which the Sun has its greatest Emissive Power. Describe this color verbally.

2) Use Planck's quantum equation to compute the energy of the "photons" of the light for the color whose wavelength was identified in part one.

3) Compute the energy of photons of light at opposite ends of the visible spectrum:

Deep Red: wavelength 7000 Angstroms

Violet: wavelength 4000 Angstroms

#### Solution Preview

...s and T in Kelvins]

Assuming that the radiation from the Sun has the same optical distribution as a black body, and using T=5800K we obtain:

lambda_max=4993 Angstroms

Looking this wavelength in a color-wavelength table such ...