Question

Choose the correct answer from the alternatives given.
If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will

• A. increase
• B. decrease
• C. remains constant
• D. first decrease then increase

Answer 1

Answer: (B)

decrease

Current through capacitor,

$I=\frac{E}{X_C}=\frac{E}{\frac{1}{\omega C}}=\omega CE=2\pi \upsilon CE$ or

$I\propto \upsilon$

$\therefore$ decrease in frequency $\upsilon$ of ac source decrease the conduction current. As displacement current is equal to conduction current, decrease in $\upsilon$ decreases displacement current in circuit.