Physics - Semiconductors Question with Solution | TestHub

In circuit $\mathrm{X}$, both the diodes are forward biased and hence both will conduct. The two resistances of $4\Omega$ each are in parallel. Their equivalent resistance is $2\Omega$. Hence the current $\mathrm{I}=\frac{\mathrm{v}}{\mathrm{R}}=\frac{8}{2}=4\mathrm{A}$ In the circuit $Y$, the diode $D_1$ is forward biased but diode $D_2$ is reverse biased. Hence only diode ${\mathrm{D}}_1$ will conduct. The resistance is $4\Omega$. Hence, $\mathrm{I}=\frac{8}{4}=2\mathrm{A}$