- #1
Pepjag
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Homework Statement
A metal ring of radius r = 24 cm surrounds a
solenoid of radius R = 2 cm and 10000 turns.
The magnetic field inside the solenoid changes from 5 T to 3 T in
0.1 s. Find the magnitude of the non-Coulomb
electric field along the ring.
Answer in units of V/m
Homework Equations
emf = -N*d(flux)/dt = -N*db/dt*A
emf = integral of E*dl
The Attempt at a Solution
Ok, so i pretty much just plugged in numbers. for the emf:
emf = -10000*(3-5)/0.1*pi*0.02^2 = 251.3 volts.
For the electric field:
E = emf/L = 251.3/2*pi*0.24 = 166.7 V/m
Unfortunately, the computer keeps saying I'm wrong. Am I really doing something wrong? This seemed pretty straight forward.