In the figure, the value of resistor R is $$\left(25+\frac{\mathrm I}2\right)\mathrm\Omega$$, where I is the current in amperes. The current I is _____.

An incandescent lamp is marked 40W, 240V. If resistance at room temperature $$\left(26^\circ\mathrm C\right)\;\mathrm{is}\;120\mathrm\Omega$$ and temperature coefficient of resistance is $$4.5\;\times\;10^{-3}/^\circ C$$ , then its ‘ON’ state filament temperature in ^oC is approximately ________.

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