Which of the following figures represents a half-wave rectifier?

Select the correct statement.

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

What is a filter circuit?

If a centre-tap transformer is used with two $p-n$ junction diodes for full-wave rectification,then the output voltage of the rectifier with respect to each diode is (secondary voltage of transformer $= V_s$)

If the maximum efficiency of a full wave rectifier is $x \%$ and that of a half wave rectifier is $y \%$,then the relation between $x$ and $y$ is