Question

An electric bulb and a capacitor are connected in series with an $AC$ source. On increasing the frequency of the source, the brightness of the bulb:

• A. increase
• B. decreses
• C. remains unchanged
• D. sometime incenses and something decreases

Answer 1

The correct option is A increase

The capacitive reactance and frequency are related as $X_c\propto \frac{1}{f}$ where f is frequency

On increasing the frequency the capacitive reactance decreases. If reactance decreases the the bulb glows with more brightness and more current flows.