The expected answers were:
(a) The liberation of electrons from an element other than the cathode of a valve by high velocity electrons
(b) (i) Focus anode
(ii) Accelerating anode
(iii) Final anode
(iv) First anode
(v) Second anode
(c) gm = transconductance
amplification factor
ra = anode resistance
(d)
The question was on Electron Emission. The question was attempted by many candidates. Many confused the parameters transconductance/mutual conductance , plate resistance, amplification factor with the device’s electrodes which incidentally was a repeat of past question. The performance was average.