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An electric lamp having coil of negligible inductance connected in series with a capacitor and an a.c. source is glowing with certain brightness, Fig. How does the brightness of the lamp change on reducing (i) capacitance (ii) frequency |
Answer» When AC source is connected , the capacitor offers capacitative reactance ` X_C-underset(omegaC)(1)=underset(2pinuC)(1)`. The current flows in the circuit and the lamp glows. (i) On reducing capacitance, `C,X_C` increases. Therefore, the brightness of the bulb reduces. (ii) On reducing frequency `v,X_C` increases. Therefore, the brightness of the bulb reduces. |
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