In a p-n junction diode, the expression for current isgiven as:
Where,
I0 =Reverse saturation current = 5 × 10−12 A
T = Absolutetemperature = 300 K
kB =Boltzmann constant = 8.6 × 10−5 eV/K = 1.376 × 10−23 JK−1
V = Voltageacross the diode
(a) Forward voltage, V = 0.6 V
∴Current, I 
.
Therefore, the forward current is about 0.0256 A.
(b) For forward voltage, V’ =0.7 V, we can write:
Hence, the increase in current, ΔI = I‘ − I
= 1.257 −0.0256 = 1.23 A
(c) Dynamic resistance 
(d) If the reverse bias voltage changes from 1 V to 2 V,then the current (I)will almost remain equal to I0 in both cases. Therefore, the dynamicresistance in the reverse bias will be infinite.