Solution:

Draw the voltage follower using op-amp and show that its gain is unity.

When $R_1=\infty$ and $R_F=0$ the non-inverting amplifier gets converted into a voltage follower or unity gain amplifier.

When the non-inverting amplifier is configured so as to obtain a gain 1, it is called a voltage follower or unity gain ample The voltage follower configuration of fig (a) is obtained by short-circuiting $R_F$ and open circuiting $R_1$ connected in the usual.

Thus all the output voltage is feedback to the inverting input of the op-amp. Therefore the feedback factor of this circuit is one.

the closed loop gain of a non -inverting amplifier:-

$ A V F=1+\frac{R_F}{R_1} $

substitute the values of $R_F=0$ and $R_1=\infty$

$ \therefore A V_F=1 $

$\therefore$ The closed loop gain of the voltage follower is 1.

The output voltage will be equal to and in phase with the input voltage. Thus voltage follower is a non-inverting ample with a voltage gain of unity.