When output of non inverting amplifier is fed back directly to inverting input then gain will be 1?

No, the gain of a non-inverting amplifier with feedback connected directly from the output to the inverting input will not be 1. The gain of a non-inverting amplifier is typically calculated using the formula:

Gain = 1 + (R2 / R1)

Where R1 is the resistance connected to the inverting input and R2 is the resistance connected to the non-inverting input. If the feedback is connected directly from the output to the inverting input, the gain will still be determined by the values of R1 and R2, not by the feedback connection alone.

No