When the non-inverting input terminal of an op-amp is equal to that of the inverting input terminal (ideally)
(a) a–>∞
(b) Vid ≅ 0
(c) AF = 1+( RF / R1)
(d) All of the mentioned
I had been asked this question in my homework.
The question is from Voltage Series Feedback Amplifier in portion Operational Amplifier Characteristics of Linear Integrated Circuits