DAY 6 – DAW February

Mean and r m s values in AC circuits; DC and AC circuits with R, L and C components; Series and parallel resonances; Quality factor; Principle of transformer.


Q 1. A 10Ω10 \Omega resistor is connected in series with a capacitor of 1μF1 \mu F and a battery with emf 12V12V. Before the switch is closed at time t=0t=0, the capacitor is uncharged. Calculate the following: (i) The time constant (ii) What fraction of the final charge is on the plates at the time t=46s.t=46 s.(iii) What fraction of the initial current remains at the time t=46s.t=46s. Consider that the internal resistance of the battery is zero and neglect the resistance of all the connecting wires. [15 marks]

Q 2. A series RLC circuit has R=2ΩR= 2 \Omega . The energy stored in the circuit decreases by 1% per period of oscillation. Its natural undamped frequency is 2kHz2 kHz . Determine the values of the inductor and the quality factor.[15 marks]

Video Solution at 11 pm