The diagram above illustrates a structure of a typical photocell. (i) Identify each of the parts labelled A and B. (ii) State one function each of A and B (iii) Einstein’s photoelectric equation can be written as E = hf – Wo. State what each of the terms E, hf and Wo represent. (b) A photon is incident on a metal whose work function is 1.32 eV. An electron is emitted from the surface with a maximum kinetic energy of 1.97 eV. Calculate the frequency of the photon. [1 eV = 1.6 x 10-19 J] (c)(i) Define half-life of a radioactive element. (ii) Sketch a graph of the relation N = Noe-\lambdat and indicate the half-life.