An ideal solenoid (N 1 turns, length 1 , radius r 1 ) is placed inside another ideal solenoid (N 2 turns, length 2 1 , radius r 2 r 1 ) such that the axes of the two coincide If the current in the outer solenoid is changing at a rate I 2 t, what is the magnitude of the induced emf in the inner sole...

An ideal solenoid (N 1 turns, length 1 , radius r 1 ) is placed inside

Question:

An ideal solenoid (N₁ turns, length ℓ₁, radius r₁) is placed inside another ideal solenoid (N₂ turns, length ℓ₂ > ℓ₁, radius r₂ > r₁) such that the axes of the two coincide. If the current in the outer solenoid is changing at a rate ΔI₂/Δt, what is the magnitude of the induced emf in the inner solenoid?