Question

The gain of the first order low pass filter

(a) Increases at the rate 20dB/decade

(b) Increases at the rate 40dB/decade

(c) Decreases at the rate 20dB/decade

(d) Decreases at the rate 40dB/decade

I have been asked this question in examination.

I'd like to ask this question from Active Filters topic in chapter Active Filters of Linear Integrated Circuits

Answer 1

Correct option is (c) Decreases at the rate 20dB/decade

In the realm of explanation: The rate at which the gain of the filter changes in the stop band is determined by the order of filter. So, for a low pass filter the gain decreases at the rate of 20dB/decade.