Question

A two-stage amplifier has an input power of 30μW and an output power of 1.5mW. One stage has a gain of 3. What is the gain of the second stage?

(a) 20

(b) 16.6

(c) 40

(d) 22.36

I have been asked this question during an interview.

I would like to ask this question from Gain, Attenuation & Decibels in portion Fundamentals of Electronics of Avionics

Answer 1

Right option is (b) 16.6

Easy explanation: Total gain = 1.5×10^-3/30×10^-6 = 50 = stage 1 gain x stage 2 gain

         Stage 2 gain = 50 / 3 = 16.6.