The changing area stops at the field edge

A uniform magnetic field along +z is confined to a circular region of radius 0.10 m and increases at 4.0 T/s. Compare the induced electric-field magnitudes at concentric radii r₁=0.050 m and r₂=0.20 m.

What is |E₂|/|E₁|?

Organize the givens & assumptions

Field-region radius: 0.10 m
dB_z/dt=4.0 T/s
Observation radii: 0.050 m and 0.20 m

Ideal cylindrical symmetry; induced field only; disregard edge fringing and additional electrostatic fields. No conducting ring is needed.

A $4$
B $0.25$
C $2$
D $1$

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