An ideal OPAMP circuit with a sinusoidal input is shown in the figure. The 3 dB frequency is the frequency at which the magnitude of the voltage gain decreases by 3 dB from the maximum value. Which of the options is/are correct?

For the circuit with an ideal OPAMP shown in the figure. $V_{\text {REF }}$ is fixed.

If $V_{\text {OUT }}=1$ volt for $V_{\text {IN }}=0.1$ volt and $V_{\text {OUT }}=6$ volt, for $V_{\text {IN }}=1 \mathrm{~V}$, where $V_{\text {OUT }}$ is measured across $R_{\mathrm{L}}$ connected at the output of this OPAMP. The value of $R_{\mathrm{F}} / R_{\text {IN }}$ is

Consider the circuit with an ideal OPAMP shown in the figure.

Assuming $\left|V_{\mathrm{IN}}\right| \ll\left|V_{\mathrm{CC}}\right|$ and $\left|V_{\mathrm{REF}}\right| \ll\left|V_{\mathrm{CC}}\right|$. The condition at which $V_{\text {OUT }}$ equals to zero is

A circuit with an ideal OPAMP is shown in the figure. A plus $V_{\text {IN }}$ of 20 ms duration is applied to the input. The capacitors are initially uncharged.

The output voltage $V_{\text {OUT }}$ of this circuit at $\tau=0^{+}$(in integer) is $\_\_\_\_$ V.