The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be:

100

The voltage gain of the amplifier with negative feedback is

$A'=\frac{A}{1+βA}$

Where, A = voltage gain without feedback

β = feedback factor

Here, A' =10, β = 9% = 0.09

$∴10=\frac{A}{1+0.09A}$

$10 + 0.9 A = A$

$A (1 – 0.9) = 0$

$A=\frac{10}{0.1}=100$