A combination of 1μF capacitor with an initial voltage V_c(0) = −2V in series with a 100Ω resistor is connected to a 20 mA ideal dc current source by operating both switches at t = 0s as shown. Which of the following graphs shown in the options approximates the voltage V_s across the current source over the next few seconds?

C₀ is the capacitance of a parallel plate capacitor with air as dielectric (as in figure (a)). If, half of the entire gap as shown in figure (b) is filled with a dielectric of permittivity $$\in_r$$ , the expression for the modified capacitance is

The reading of voltmeter $$(rms)$$ in volts, for the circuit shown in the figure is ______.

The dc current flowing in a circuit is measured by two ammeters, one PMMC and another electrodynamometer type, connected in series. The PMMC meter contains 100 turns in the coil, the flux density in the air gap is 0.2 Wb/m² , and the area of the coil is 80 mm². The electrodynamometer ammeter has a change in mutual inductance with respect to deflection of 0.5 mH/deg. The spring constants of both the meters are equal. The value of current, it which the deflection of the two meters are same, is ___________.