Answer:
I = 5.3 102 A
Explanation:
The magnetic field created by a solenoid is
B = μ₀ N/L I
Where B the magnetic field, N the number of turns, L the length of the solenoid and I the current flowing
I = B L / μ₀ N
Let's reduce to the SI system
L = 38 cm = 0.38 m
Let's calculate
I = 5.0 10⁻⁵ 0.38 / (450 4π 10⁻⁷)
I = 5.3 102 A