For the given diagram of barrier potential of this diode is 0.5 V. The value of current in the circuit is:

$\frac{1}{20} A$

The correct answer is Option (2) → $\frac{1}{20} A$

Net potential across the Resistor,

$Emf_{net}=Emf-V_{barrier}$

$=(5-0.5)V$

$=4.5V$

and,

$V=IR$ [Ohm's law]

$I=\frac{V_{net}}{R}=\frac{4.5}{90}=\frac{45}{900}=\frac{1}{20}A$