Answer:
0.31 T
Explanation:
N = 1750
R = 30 ohm
A = 5 x 10^-4 m^2
B1 = 0 T
q = 9 x 10^-3 C
Let the magnetic field is B ad the time is t.
B2 = B
Use the Faraday's law of electromagnetic induction
e = dФ / dt
i R = N x A x (B2 - B1) / t
i x R / t = N x A x B
q x R = N x A x B
9 x 10^-3 x 30 = 1750 x 5 x 10^-4 x B
B = 0.31 T