Electro Magnetic Induction And Alternating Currents Question 126
Question: Assertion : An electric lamp connected in series with a variable capacitor and ac source, its brightness increases with increase in capacitance. Reason : Capacitive reactance decrease with increase in capacitance of capacitor.
Options:
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 reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: A
Solution:
Capacitive reactance $ X_{C}=\frac{1}{\omega C}. $ When capacitance increases, the capacitive reactance decreases. Due to decrease in its values, the current in the circuit will increases $ ( I=\frac{E}{\sqrt{R^{2}+X_{C}^{2}}} ) $ and hence brightness of source (or electric lamp) will also increases.
