In the opamp circuit shown, the Zener diodes Z1 and Z2 clamp the output voltage V_o to +5 V or -5 V. The switch S is intially closed and is opened at time t = 0

The time t = t_{1 (in seconds) at which Vo changes state is _____.}

A p-i-n photo diode of responsivity 0.8A/W is connected to the inverting input of an ideal opamp as shown in the figure, +V_CC = 15V, - V_CC = -15V, Load resistor R_L = 10 k$$\Omega $$ . If 10$$\mu $$W of power is incident on the photodiode, then the value of the photocurrent (in $$\mu $$A) through the load is _____.

An ideal opamp has voltage source V₁, V₃, V₅, ......, V_N-1, connected to the non- inverting input and V₂, V₄, V₆, .....V_N connected to the inverting input as shown in the figure below (+V_CC= 15 volt, -V_CC = -15 volt). The voltage V₁, V₂, V₃,V₄, V₅, V₆ ....... are 1, -1/2, 1/3, -1/4, 1/5, -1/6, .... volt, respectively. As N approaches infinity, the output voltage (in volt) is _______

For the circuit shown in the figure, R₁ = R₂ = R₃ = 1 Ω, L = 1 µH and C = 1 µF. If the input V_in = cos(10⁶t) , then the overall voltage gain (V_out /V_in) of the circuit is __________.