Three identical coils C₁, C₂ and C₃ are closely placed such that they share a common axis. C₂ is exactly midway. C₁ carries current I in anti-clockwise direction while C₃ carries current I in clockwise direction. An induced current flows through C₂ will be in clockwise direction when
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Question

Three identical coils C₁, C₂ and C₃ are closely placed such that they share a common axis. C₂ is exactly midway. C₁ carries current I in anti-clockwise direction while C₃ carries current I in clockwise direction. An induced current flows through C₂ will be in clockwise direction when

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G1 Physics · Accepted Answer

The currents in C₁ and C₃ are opposite, so the magnetic fields they produce through the middle coil C₂ are in opposite directions. In the source orientation, the net flux through C₂ may be written as the difference of the two contributions: Φ = [B(C₃) - B(C₁)]A. If C₁ moves towards C₂, the magnitude of B(C₁) through C₂ increases. If at the same time C₃ moves away from C₂, the magnitude of B(C₃) through C₂ decreases. Therefore the net magnetic flux through C₂ changes in the direction correspondi…