practical sense, explain why an op-amp will have an output voltage even if its input voltage is zero

Draw the circuit symbol for an op amp, adding sources to account for dc imperfections.

When 100 V and 20 V are applied to the non inverting and the inverting terminal of open loop an opamp, the output obtained is 80600 V.  If the voltage at the inverting terminal is changed to 40 V, then the output voltage is 60700 V.  What will be the differential gain and common mode gain of the opamp?

Define operational amplifiers (op - amps) and discuss their characteristics, such as high gain, input impedance, and output impedance. Explain common op-amp configurations and their applications in signal processing and control systems.