Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). 
Assertion (A): Choke coil is simply a coil having a large inductance but a small resistance. Choke coils are used with fluorescent mercury-tube fittings. If household electric power is directly connected to a mercury tube, the tube will be damaged. 
Reason (R): By using the choke coil, the voltage across the tube is reduced by a factor \( \frac{R}{\sqrt{R^2 + \omega^2 L^2}} \), where \( \omega \) is the frequency of the supply across resistor \( R \) and inductor \( L \). If the choke coil were not used, the voltage across the resistor would be the same as the applied voltage. 
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are true and (R) is the correct explanation of (A)
• B. (A) is false but (R) is true
• C. Both (A) and (R) are true but (R) is not the correct explanation of (A)
• D. (A) is true but (R) is false

Hint:

When evaluating the correctness of a statement and its explanation, ensure that the explanation correctly justifies the assertion. In cases involving physics concepts, consider the physical principles and equations that govern the phenomena.

Answer 1

The Correct Option is D

Assertion (A) is true: A choke coil is employed to limit current in fluorescent tube circuits, and its substantial inductance allows it to function as a resistor in AC circuits.
Reason (R) is false: The voltage reduction factor requires calculation based on the coil's reactance and resistance; the provided explanation is insufficient and inaccurate for this scenario. Therefore, the correct option is (4).