Assuming in forward bias condition there is a voltage drop of 0.7V across a silicon diode, the current through diode $$D_{1}$$ in the circuit is ___ mA.
(Assume all diodes in the given circuit are identical)

Diodes D1 and D3 are forward-biased (ON).
Diode D2 is reverse-biased (OFF) and acts as an open circuit. Because $$D_1$$ and $$D_3$$ are in parallel, the voltage drop across this entire parallel combination is $$0.7\text{ V}$$.

The voltage across the resistor $$R_1$$

$$ V_{R1} = 12\text{ V} - 0.7\text{ V} = 11.3\text{ V} $$

$$ I_{\text{total}} = \frac{V_{R1}}{R_1} = \frac{11.3\text{ V}}{0.3\text{ k}\Omega} $$

$$ I_{\text{total}} = \frac{11.3}{0.3}\text{ mA} = \frac{113}{3}\text{ mA} $$

$$D_1$$ and $$D_3$$ are indentical and in parallel, the total current splits equally between them.

$$ I_{D1} = \frac{I_{\text{total}}}{2} $$

$$ I_{D1} = \frac{113/3\text{ mA}}{2} = \frac{113}{6}\text{ mA} $$

$$ I_{D1} \approx 18.83\text{ mA} $$