In a full wave rectifier circuit operating from 50 Hz moving frequency, the fundamental frequency in the ripple would be  (in Hz)

$In full wave rectifier, we get the output for the positive and negative cycle of input a.c.$

$Hence the frequency of the ripple of the output is twice than that of input a.c.$

$$\begin{gathered} Frequency =2\times input frequency \\ =2\times 50=100 Hz \end{gathered}$$