If $$V_A-V_B=\;6\;V$$, then $$V_C-V_D$$ is

Assuming both the voltage sources are in phase, the value of R for which maximum power is transferred from circuit A to circuit B is

In the following figure, C₁ and C₂ are ideal capacitors. C₁ has been charged to 12 V before the ideal switch S is closed at t = 0. The current i(t) for all t is

The average power delivered to an impedance $$\left(4-j3\right)$$ Ω by a current $$5\cos\left(100\mathrm{πt}+100\right)\;A$$ is