AC Fluctuations in Bulbs – Rankers Physics

LR, RC and LCR Circuits: Practice Problem & Solution

Assertion (A): In ac supply we cannot feel any fluctuations of current in bulbs. Reason (R): House hold ac supply has very low frequency.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of LR, RC and LCR Circuits. Understanding the underlying formula is key to arriving at the correct answer below:

Our eyes cannot detect flickers above \(10-15 \text{ Hz}\). Household AC supply (\(50/60 \text{ Hz}\)) changes too rapidly for us to perceive fluctuations in bulbs. Thus, Assertion (A) is true. However, \(50/60 \text{ Hz}\) is not considered a "very low frequency", thus Reason (R) is false.

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