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Q110 (CDS-II/2019) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

If the speed of a moving magnet inside a coil increases the electric current in the coil-

Result
Your answer: —  Â·  Correct: A
Explanation

According to Faraday's Law of electromagnetic induction, the induced electromotive force (EMF) in a closed circuit is directly proportional to the rate of change of magnetic flux through the circuit. When a magnet moves inside a coil, it creates a changing magnetic field that induces an electric current [2]. The magnitude of this induced EMF is mathematically expressed as EMF = -N ΔΦ/Δt, where Δt represents the time interval. If the speed of the moving magnet increases, the time taken for the magnetic flux to change (Δt) decreases, which significantly increases the rate of change of flux (ΔΦ/Δt). Consequently, a higher speed results in a greater induced EMF and a larger electric current flowing through the coil. This relationship confirms that faster relative motion between the magnet and the coil leads to an increased current.

Sources

  1. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 4: Electricity: Magnetic and Heating Effects > A step further > p. 52
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