(1 point) In a photoelectric experiment using a lithium surface, you find a stopping potential of 0.72 V for a wavelength of 342 nm and a stopping potential of 2.89 V for a wavelength of 214 nm. Because this is an experiment, your value of Planck's constant will be slightly different from the official value. From these data find: a) a value for Planck's constant, h: x10'34 J - s b) the work function for lithium: eV 0) the cutoff wavelength for this metal: nm