Question

Metal detector works on the principle of

• A. Ohm's law
• B. Couloumb's Law
• C. Electromagnetic induction
• D. Stefan's law of radiation

Answer 1

The Correct Option is C

To solve the problem, we need to identify the correct physical principle behind the operation of a metal detector.

1. Understanding Metal Detectors:
Metal detectors typically use a coil of wire through which an alternating current is passed. This generates a time-varying magnetic field. When a metal object is present nearby, it alters this magnetic field, often by inducing eddy currents in the metal. These eddy currents, in turn, produce their own magnetic fields, which can be detected by the sensor.

2. Relevant Principle:
This behavior is governed by Faraday’s Law of Electromagnetic Induction, which states that a changing magnetic field induces an electromotive force (EMF) in a conductor. The principle of electromagnetic induction is what allows metal detectors to sense nearby conductive objects.

3. Eliminating Incorrect Options:
- Ohm’s law relates voltage, current, and resistance: not relevant here.
- Coulomb’s law describes electrostatic force: not related to detection of metals.
- Stefan’s law relates to blackbody radiation: not applicable in this context.
- Electromagnetic induction: correct, as it is the working principle behind how metal detectors detect metal objects.

Final Answer:
Metal detectors work on the principle of Electromagnetic Induction.