(Estimation of the Planck constant)
When two ultraviolet beams of wavelengths λ1=80 nm and λ2=110 nm fall on a lead surface, they produce photoelectrons with maximum energies 11.390 eV and 7.154 eV, respectively.
(a) Estimate the numerical value of the Planck constant.
(b) Calculate the work function, the cutoff frequency, and the cutoff wavelength of lead.