A photoelectric experiment using a cesium metal surface produces stopping potentials of 0.95V and 0.38V using light with wavelengths of 435.8nm and 546.1nm, respectively. Using only this data together with the values of the speed of light and the charge on the electron, find
(a) the value of Planck's constant,
(b) the work function for cesium (in eV) and
(c) the threshold frequency.