The graph shows the variation with the time of the power dissipated in a resistor of resistance $2.0 \Omega$  In an ac circuit.

What is the rms value of the voltage across the resistor (in $\Omega$) and the period of the current (in s)?

In the circuit shows a capacitor that is initially uncharged is being charged by a battery.

Which of the following is a correct graph of the variation of the potential difference $\mathrm{V}$ across the plates with charge $\mathrm{q}$ on one of the capacitor plates?

What will the initial current be in the below the instant the switch is closed, and what will it be eventually a long time after the switch is closed? (answer in order)

The graph shows the variation with time t of the current I for a discharging capacitor.

What is the time constant of this system?(in sec)

The diagram shows a charged parallel plate capacitor in a vacuum connected to an ideal voltmeter. The reading on the voltmeter is 9.0V.

Explain why the capacitor does not discharge.