If the unit step response of a network is $$(1-e^{-\alpha t})$$, then its unit impulse response is

In the circuit shown below, the initial charge on the capacitor is 2.5 mC, with the voltage polarity as indicated. The switch is closed at time t=0. The current i(t) at a time t after the switch is closed is

In the circuit shown below, the network N is described by the following Y matrix: $$$Y\;=\;\begin{bmatrix}0.1S&-0.01S\\0.01S&0.1S\end{bmatrix}$$$ The voltage gain $$\frac{V_2}{V_1}$$ is

In the circuit shown below, the current I is equal to