Final answer:
An ideal operational amplifier is characterized by having an input impedance of infinity which means it draws no current at its inputs.
Step-by-step explanation:
The student is asking about the input impedance of an ideal operational amplifier (op-amp). In an ideal operational amplifier, the input impedance is infinity, which means the input does not draw any current.
However, in practice, no op-amp can achieve infinite impedance, but modern op-amps can have very high input impedances, effectively approximating the ideal. A high input impedance allows for the op-amp to be used in a wide variety of applications without affecting the preceding circuitry.