Question

The capacitor blocks AC but passes DC.

• A. True
• B. False

Answer 1

The correct option is B False

Explanation

The capacitor blocks direct current (DC) but passes alternate current (AC).

We know the reactance of a capacitor, capacitive reactance,

$X_C=\frac{1}{2\mathrm{\pi fC}}$

From the equation, it is clear that capacitive reactance is inversely proportional to frequency.

1. In the case of a DC, frequency is zero, therefore capacitive reactance is infinity. Since capacitive reactance is the resistance of the capacitor, when it is infinity current does not flow through the capacitor. i.e., the capacitor blocks DC.
2. In the case of AC, the frequency is non-zero, therefore the capacitive reactance is not infinity, and therefore the current flows. The capacitor allows AC to pass.

Thus, the capacitor blocks DC but passes AC.

Hence, the given statement is false.