1. a) A photo diode has a quantum efficiency of 65% when photons of energy 1.5x10-19) are incident on it. Calculate (i) The operating wavelength (5 Marks) (ii) Responsivity (5 Marks) (iii) The incident power required to obtain a photocurrent of 2.5uA. (2 Marks) b) Discuss the working principle of Eddy Current Sensors with a neat diagram. Mention any two applications of eddy current sensors. (8 Marks)