13. Source and drain in nMOS device are isolated by a) a single diode b) two diodes c) three diodes d) four diodes 14. In enhancement mode, device is normally in a) conducting b) non conducting c) partially conducting d) insulating 15. nMOS devices are formed in a) p-type substrate of high doping level b) n-type substrate of low doping level c) p-type substrate of moderate doping level d) n-type substrate of high doping level condition