JEE Main202622 January 2026Morning ShiftPhysicsElectromagnetic InductionActual
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
Options
- AC₁ moves away from C₂ and C₃ moves towards C₂
- BC₁ and C₃ move with equal speeds away from C₂
- CC₁ moves towards C₂ and C₃ moves away from C₂
- DC₁ and C₃ move with equal speeds towards C₂
Correct answer
C. C₁ moves towards C₂ and C₃ moves away from C₂
Step-by-step solution
Let the common axis be the z-axis. C₁ is at z = -d , C₂ is at z = 0 , and C₃ is at z = +d . Current in C₁ is anti-clockwise (ACW), producing a magnetic field B₁ in the +z direction at C₂ . Current in C₃ is clockwise (CW), producing a magnetic field B₃ in the -z direction at C₂ . The net magnetic field at C₂ is B_ net = B₁ - B₃ . Since C₁ and C₃ are equidistant and carry equal current, initially B_ net = 0 . To induce a clockwise current in C₂ , Lenz's law states that the induced current must oppose the change in fl