In the Figures (a) and (b) shown below, the transformers are identical and ideal ,except that the transformer in Figure (b) is centre -tapped. Asssuming ideal diodes, the ratio of the root mean-square (RMS) voltage across the resistor R in Figure (a) to that in figure (b) is
- $\sqrt{2}$: 1
- 2: 1
- 2$\sqrt{2}$ : 1
- 4:1
