A Perfectly Black Sphere 18

Short Answer

A perfectly black sphere 18.0 cm in diameter is held at a temperature of 215°C. (σ = 5.670 × 10-8 W/m² ∙ K⁴, Wien displacement law constant is 2.90 × 10^-3 m ∙ K, h = 6.626 × 10^-34 J ∙ s, c = 3.00 × 10⁸ m/s)
(a) Near what wavelength does this sphere radiate most strongly?
(b) If all the radiated energy were at the wavelength found in part (a), how many photons would the sphere emit each second?