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 because a choke coil is indeed used to limit the current in a circuit with fluorescent tubes, and its high inductance ensures that it behaves like a resistor in the AC circuit. 
Reason (R) is false because the voltage reduction factor should be more accurately derived based on the reactance of the coil and the resistance, and the reason provided is incomplete and incorrect in this context. Thus, the correct answer is (4).