(a(i))[2]
Negative feedback can be used in amplifier circuits. State what is meant by negative feedback.
(a(ii))[2]
State two effects of negative feedback on an amplifier that contains an operational amplifier (op-amp).
(b(i))[1]
Fig. 9.1 shows an amplifier circuit connected to a microphone. The output potential difference $V_{\text{OUT}}$ is $4.4\,\text{V}$ when the potential at point $P$ is $62\,\text{mV}$. Determine the gain of the amplifier.
(b(ii))[2]
Determine the resistance of the resistor $R$.
(c)[3]
The greatest potential difference produced by the microphone at point $P$ on Fig. 9.1 is $95\,\text{mV}$. The power supply for the operational amplifier can be either $+/-5\,\text{V}$ or $+/-9\,\text{V}$. State which power supply should be used. Justify your answer quantitatively.