Discussion
An amplifier having open loop gain of 100 is provided with a negative feedback having feedback factor of 0.02. The gain of the amplifier after feedback will be :
Answer: B
The gain with feedback is 33.33.
With negative feedback, the closed-loop gain is:
\[ \begin{aligned} A_{f} &= \frac{A}{1 + A\beta} \\ &= \frac{100}{1 + 100 \times 0.02} \\ &= \frac{100}{3} \approx 33.33 \end{aligned} \]
Negative feedback trades gain for stability and bandwidth, so the gain falls by the factor \(1 + A\beta = 3\). The value 50.00 is \(1/\beta\), the approximation that holds only when \(A\beta \gg 1\); here \(A\beta = 2\), so it does not apply. The other values do not follow from the formula.
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