Question
A bulb and a capacitor are connected in series to an a.c. source of variable frequency. How will the brightness of the bulb change on increasing the frequency of the a.c. source?
Solution
Capacitive reactance and frequency has an inverse dependent (Xc ∝ 1/f).
Thus, as the frequency of the a.c. source increases, the capacitive reactance decreases. Therefore, the bulb glows with more brightness because more current flows through it.
Thus, as the frequency of the a.c. source increases, the capacitive reactance decreases. Therefore, the bulb glows with more brightness because more current flows through it.
