| Assertion: An electric lamp connected in series with a variable capacitor and A.C. source, its brightness increases with increase in capacitance. |
| Reason: Capacitive reactance decreases with increase in capacitance of capacitor. |
A) If both assertion and reason are true and reason is the correct explanation of assertion.
B) If both assertion and reason are true and reason is not the correct explanation of assertion.
C) If assertion is true but reason is false.
D) If both assertion and reason are false.
E) If assertion is false but reason is true.
Correct Answer: A
Solution :
Capacitive reactance \[{{X}_{C}}=\frac{1}{\omega C}\], when capacitance C increases, the capacitive reactance decreases. Due to decrease in its values, the current in the circuit will increase \[\left( I=\frac{E}{\sqrt{{{R}^{2}}+X_{C}^{2}}} \right)\]and hence brightness of source (or electric lamp) will also increase.
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