Direction for: In each of the following questions a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements mark the correct answer as
Assertion For an electric lamp connected in series with a variable capacitor and AC 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 the Reason is the correct explanation of the Assertion
B) if both Assertion and Reason are true but the Reason is nor the correct explanation of the Assertion
C) if Assertion is true but Reason is false
D) if Assertion and Reason are false
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 \[\left( 1=\frac{E}{\sqrt{{{R}^{2}}+X_{C}^{2}}} \right)\] and hence brightness of source (or electric lamp) will also increase.
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