To answer this part use a graph from lecturenotes: I vs Vs.
(i)When the polarity is reversed is the stopping potential is 2.09V , any magnitude greater that 2.09V will give I=0
(ii) When the polarity is as shown in diagram it is accelerating potential , no change in current as it has reached saturation.
(iii) When the work function is increased and the photon energy is less than work function , then nothing happens (I=0) , no photo electrons are emitted.
