Metal Detector Principle – Rankers Physics

LR, RC and LCR Circuits: Practice Problem & Solution

Assertion (A): At an airport, a person is made to walk through the doorway of a metal detector. Reason (R): Metal detector works on the principle of resonance in \(AC\) circuits.  
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

Short Solution (Best for NEET):

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:

Metal detectors use \(LC\) resonant circuits. When a metal object enters the coil's magnetic field, it changes the coil's inductance, altering the circuit's resonant frequency and triggering detection.

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