Draw the circuit diagram of a full wave rectifier. Briefly explain its working.

In the circuit shown in Figure contains two diodes $D_1$ and $D_2,$ each with a forward resistance of $50\Omega$ and infinite backward resistance. If the battery voltage is $6 \mathrm{V},$ Find the current through the $100\Omega$ resistance.

The base-current of a transistor is $105\mu \mathrm{A}$ and the collector current is $2.05 \mathrm{mA}.$

Find the ${\beta }_{dc}$ and ${\alpha }_{dc}$ of the transistor.