The orbiting space shuttle moved around Earth well above 99 percent of the atmosphere, yet it still accumulated an electric charge on its skin due, in part, to the loss of electrons caused by the photoelectric effect with sunlight. Suppose the skin of the shuttle were coated with Ni, which has a relatively large work function ф = 4.87 eV at the temperatures encountered in orbit. 

(a) What is the maximum wavelength in the solar spectrum
that could result in the emission of photoelectrons from the shuttle’s skin? 

(b) What is the maximum fraction of the total power falling on the shuttle that potentially could have produced photoelectrons?