Final answer:
To calculate the fraction of the output fed back in an amplifier, use the formula β = (α - α') / (α × α') with α as the gain without feedback and α' as the gain with feedback. The calculated feedback fraction for the given amplifier is 1/125 or 0.008.
Step-by-step explanation:
The question asks how to calculate the fraction of the output fed back in an amplifier when negative feedback is applied, which reduces its gain from 500 to 100. This calculation can be done using the formula for feedback fraction, β = (α - α') / (α × α'), where α is the gain without feedback and α' is the gain with feedback. For the given amplifier, α = 500 and α' = 100.
To find β, we insert the given values into the formula: β = (500 - 100) / (500 × 100) = 400 / 50000 = 1/125 or 0.008.
This is the fraction of the output that is fed back into the input to achieve a reduced gain with feedback.