Correct Answer - Option 4 : increase in overall gain and reduction in overall bandwidth
Effect of cascading on the cutoff frequency and Bandwidth:
If n-Identical non-interacting amplifiers are cascaded and each amplifier has an individual cutoff frequency fL1 and fH1 then the overall cutoff freq. of the cascaded amplifier will be:
\({f_L} = \frac{{{f_{{L_1}}}}}{{\sqrt {{2^{1/N}} - 1} }}\)
\({f_H^*} = {f_{{H}}} \times \sqrt {{2^{1/N}} - 1} \)
For,
\(\sqrt {{2^{1/N}} - 1} < 1\)
\({f_L} > {f_{{L_1}}}\;\;\& \;\;{f_H} < {f_{{H_1}}}\)
Note: Cascading Increases lower cutoff and decreases higher cutoff frequency hence bandwidth decreases.
In cascading connection voltage gain increases which in turn reduces the bandwidth to maintain a constant gain-bandwidth product.
The same analysis is valid for cascading n = 2 amplifiers.