I = 28.6mA.
The magnetic field in the center of a solenoid is given by:
B = μ₀NI/L
Clear I from the equation above, we obtain:
I = BL/μ₀N
With B = 1.00 x 10⁻⁴T, L = 0.42m, μ₀ = 4π x 10⁻⁷T.m/A and N = 1170turns
I = [(1.00 x 10⁻⁴T)(0.42m)]/[(4π x 10⁻⁷T.m/A)(1170turns)]
I = 0.0286A
I = 28.6mA