A full wave rectifier circuit with diodes ($D_1$) and ($D_2$) is shown in the figure. If input supply voltage $V_{in}=220\sin (100\pi t)\text{volt}$, then at $t=15\text{msec}$:

We need to determine the state of diodes $D_1$ and $D_2$ at $t=15\text{ ms}$.1. Determine the Input PhaseThe input voltage is $V_{in}=220\sin (100\pi t)$.At $t=15\text{ ms}=0.015\text{ s}$:
$$\text{Argument}=100\pi \times 0.015=1.5\pi =\frac{3\pi }{2}$$
$\sin (3\pi /2)=-1$.2. Diode StatesSince the sine value is negative at this instant, the polarity of the secondary transformer is reversed:The top terminal of the secondary transformer (connected to $D_1$) is Negative.The bottom terminal (connected to $D_2$) is Positive.In a center-tapped rectifier during a negative half-cycle:$D_1$ is Reverse Biased (Anode is negative relative to the center tap).$D_2$ is Forward Biased (Anode is positive relative to the center tap).Correct Option: (2) $D_1$ is reverse biased, $D_2$ is forward biased