Show that the unit of the time constant (RC) is the second.

A $400\mu \mathrm{F}$ capacitor is charged using a $20 \mathrm{V}$ battery. It is connected across the ends of a $600\Omega$ resistor with $20 \mathrm{V}$ potential difference across its plates.Calculate the charge stored on the capacitor.

A $400\mu \mathrm{F}$, capacitor is charged using a $20 \mathrm{V}$, battery. It is connected across the ends of a $600\Omega$, resistor with $20 \mathrm{V}$,potential difference across its plates.

Calculate the time constant for the discharging circuit.

A $400\mu \mathrm{F}$ capacitor is charged using a $20 \mathrm{V}$ battery. It is connected across the ends of a $600\Omega$ resistor with $20 \mathrm{V}$ potential difference across its plates.

(c) Calculate the time it takes the charge on the capacitor to fall to $2.0\mathrm{mC}$.

A $400\mu \mathrm{F}$ capacitor is charged using a $20 \mathrm{V}$ battery. It is connected across the ends of a $600\Omega$ resistor with $20 \mathrm{V}$ potential difference across its plates.

(d) State the potential difference across the plates when the charge has fallen to $2.0\mathrm{mC}$.

A capacitor has a potential difference of $6.0 \mathrm{V}$ across its plates and stores $9.0 \mathrm{mJ}$ of energy. Which row in the table gives the capacitance of the capacitor and the charge on its plates?

A capacitor in an electronic circuit is designed to slowly discharge through an indicator lamp. It is decided that the time taken for the capacitor to discharge needs to be increased. Four changes are suggested:

(1) Connect a second capacitor in parallel with the original capacitor.

(2) Connect a second capacitor in series with the original capacitor.

(3) Connect a resistor in parallel with the lamp.

(4) Connect a resistor in series with the lamp.

Which suggestions would lead to the discharge time being increased?