Question

A $80\Omega$ resistor and $20\mu C$ capacitor are connected in series with an AC source of $220V - 50Hz$ . Calculate the potential difference across each of them.

Answer 1

Hint:To find the potential difference between a resistor and a capacitor connected in series with an AC source, we have to use the concept of capacitor and resistor connected in the circuit of source and the current flowing through it. We also use ohm’s law which states Voltage or potential across the circuit is proportional to the current.

Complete step by step answer:
Let us consider a circuit in which a resistor and a capacitor are connected in series with an AC source. These types of circuits are called RC circuits. Capacitors do not allow the direct current flow through it, So, the current in the circuit will be zero.Due to this, the potential across the resistance is zero as there is no current in the circuit (using ohm’s law).

But, the capacitor can be charged from zero to maximum voltage applied to its terminals. The circuit is off until the capacitor is fully charged and discharged.So, the potential across the capacitor is $220V$.
${V_r} = 0$ and ${V_C} = 220V$ .

Note:The current flows in the opposite direction of the current found when the capacitor is charging and hence there is no current in the circuit. The values of resistor and capacitor decides the value of current flowing through the circuit. These values decide the charging and discharging of the capacitor. We should note that until the capacitor is fully charged, there is no current and voltage in the circuit.